If 1980-81 turns out to be a memorable season for theater in Washington, Manny Azenberg would be happy to take some of the credit.

It was Azenberg who led the campaign to disconnect the National Theater from the Kennedy Center; and now that they're disconnected, he intends to "put our money where our mouth was." The Neil Simon/Marvin Hamlisch musical "They're Playing Our Song," which opens at the National Saturday night, is an Azenberg production. So are Mark Medoff's "Children of a Lesser God" and Neil Simon's "I Ought to Be in Pictures," the two plays that follow. Altogether, these shows will occupy the National for the next four months.

"Outside of Los Angeles or New York," he says, "I give it two years before (Washington) is the best city to play in the country." This bit of "I told you so," is uttered, Camel in mouth, from Azenburg's home turf -- the ninth floor of a slightly ramshackle office building at the corner of Broadway and 46th Street.

The building matches the man. At 46, Azenberg's mustache is verging on gray and his midsection is threatening to thicken. If he came to the office in a suit and tie, it would probably cause a small panic, and even at the theater these are accessories reserved for opening nights.Otherwise, a shirt-sleeved and sometimes blue-jeaned Azenberg can be observed watching his shows -- and his audiences -- from a low slouch in a box seat.

"Don't Invest in Show Business," proclaims a framed needlepoint in his private chambers, which are filled with plants and not, in fact, very private. Outside in the open central space of the Azenberg suite, about 25 young employees attend to the phone calls, filing and bookkeeping connected with 13 current Azenberg productions -- four companies of "They're Playing Our Song," three of "Ain't Misbehaving," two of "I Ought to Be in Pictures," two of "Children of a Lesser God," one of "Whose Life Is It Anyway?" and one (about to go into rehearsal) of Neil Simon's latest work, "The Curse of Kolyenchikov."

These titles are the here and now. The past is spread all over the walls in the form of posters for such shows as "The Lion in Winter," "Mark Twain Tonight," "The Investigation," "The Prisoner of Second Avenue" and "California Suite." The flops are there too -- "The Poison Tree," "Something's Afoot" and "Division Street," among others.

His Washington connection dates back to a conversation he says he had three years ago with Kennedy Center chairman Roger . Stevens -- a conversation Stevens says he can't recall. The subject was Azenberg's desire to have Neil Simon's "Chapter Two" play the Kennedy Center. It never did, because, according to Azenberg, Stevens never got back to him as promised. That was when Azenberg began complaining to the press, the U.S. Senate and anyone else who cared to listen about the Kennedy Center's increasing influence over the Washington theater market.

A year ago, at an informal hearing chaired by Sen. Daniel P. Moynihan (D-N.Y.), Azenberg, Simon and seven Broadway colleagues criticized Stevens for, among other alleged offenses, restricting the number of black plays and outside productions on the Center's subscription series, relegating inferior shows to the National, and generally betraying a "conservative, pro-British taste." Other producers sprang to Stevens' defense, arguing that the dispute was a matter of conflicting interests and opinions rather than principle. Stevens, they pointed out, had been the man most responsible for getting the Kennedy Center built and for rescuing the National in its mid-70's distress.

That was the high plane of the argument. Less civilized words were also spoken on both sides, and there were times when "it got scary," Azenberg recalls. "I was not happy being in that kind of league dispute." But from what he calls the "silly moment" when he decided to go public, the controversy snowballed. The Warner Theater, which he helped convert into a legitimate house, did impressive business whith two Azenberg-managed productions, "For Colored Girls . . ." and "Chapter Two." And that, along with Senate criticism of the Kennedy Center's ties to the National, got the attention of the National's board of directors, who began wondering if they should continue their management contract with the Center. They decided in the negative and, fighting off legal objections from both the Kennedy Center and theater magnate James Nederlander (who used to run the National), formed a new alliance with the Shubert Organization, the biggest chain of theaters in the nation.

As Azenberg sees it, the National's continuing appeal has already been vindicated by "Amadeus," the first production under Shubert management, which sold out the last 10 days of its month's run. "If it were not on its way to Broadway, I venture to say 'Amadeus' could have stayed in Washington another three months," says Azenberg.

In short, "I think it turned out okay," he says. "It will only get better . . . I do take some credit. I think it happened because we got angry."

Azenberg's producing career began, technically, with "The Lion in Winter," which he co-produced with Eugene Wolsk in 1966, after both men had left the David Merrick organization and struck out on their own. But in another sense, Azenberg's career began on the playing fields of Central Park. One of the shows he supervised for Merrick was "Sunday in New York," and he and star Robert Redford anchored the "Sunday in New York" softball team in the Broadway show league. Later, Redford went into Simon's "Barefoot in the Park," a four-character play that couldn't support a proper team. So Azenberg, among other ringers, was recruited to help fill the gap.

Redford played first base. Azenberg played shortstop. Simon played second base. "Good field -- no hit" was Azenberg's first impression of the man whose plays he has now been producing for a decade. "I always told Neil he'd never have made the team if he didn't own it."

As a one-time promotional executive at Madison Square Garden, Azenberg was friendly with Knicks forward Bill Bradley and Dave Debusschere, and he and Simon got into a basketball-and-dinner habit during the Knick's heyday after 1969. On Memorial Day 1971, Simon asked Azenberg to pay him a visit, and sprang an unexpected question. "How'd you like to produce my plays?" he asked. Then he handed Azenberg a script. It was "The Sunshine Boys."

Walking home that night, "I think I may not have touched the ground," says Azenberg. "I was stunned . . . And it worked out kind of wonderfully. sHe's the consummate professional and he's always prepared. I think one can safely say that on every one of his plays, there are four to five drafts before rehearsal."

Because of Simon's spectacular commercial success and his unique ability to finance his own productions, Azenberg allows that their relationship has not been the usual one between a producer and playwright. "I'm very intimidated," he says. "Totally . . . The first time around, I remember making one suggestion. I had a perception of a scene and he said, 'You know, you're right,' and he left the table and did some rewriting and I felt wonderful."

The audience is Simon's main guide, according to Azenberg. "Is the audience laughing? Is the audience coughing?" Nor will just any kind of laughter do. "There's a thing that Neil calls a 'half-laugh.' He says you must get rid of all the half-laughs. That's when the audience is expecting to laugh and it doesn't quite work. You've got to improve it or cut it." But the changes don't always come easily. One play ended with a curtain line about hemorrhoids, and when Azenberg suggested that a better subject could be found for such an important moment, the author replied, "Don't you think I know it? I didn't have anything better." Azanberg is aware, of course, that his prize playwright has his detractors. "He has made a lot of money. There are many people out there who would like to make that money too . . . Give him credit for the fact that he writes for the theater [as contrasted with the easier living that might be had in movies and television]. Everybody has an excuse for why they don't." Azanberg mentions William Goldman, Paddy Chayesfsky and Larry Gelbart as able sometime-playwrights who don't. "And if you think he does it for the money, you're not 2 percent wrong, you're 100 percent wrong.

"If Neil Simon is remembered, when all is said and done, for 'The Odd Couple' and 'The Sunshine Boys,' that ain't bad. I don't think Neil writes for immortality."

The Washington cast of "They're Playing Our Song" will be headed by Victor Garber and Marsha Skaggs, who are not household figures. "We've discovered that there are very few genuine stars that meaningful," says Azenberg. "There are a lot of 'names.' Neil's philosophy for the road has always been going for the best people possible. He doesn't go for the names. We're artistically more than pleased with these people."

Yet Azenberg was the producer with the inspired notion of casting Mary Tyler Moore in "Whose Life Is It Anyway?" -- in what had been a man's role. That coup not only extended the life of the play but rekindled memories of a brand of showmanship that has all but vanished from the Broadway theater.(Azenberg may have learned such lessons from Merrick, the most flamboyant of Broadway's modern showmen. The only lesson he admits to, however, is the virtue of starting work early and leaving late).

There have been other occasions when Azenberg has had no such tricks up his sleeve. Two of the plays he produced last season, Frank Gilroy's "Last Licks" and Abe Polsky's "Devour the Snow" (about the Donner Pass crossing), were instant, total flops within weeks of each other. How does it feel to have your judgement so quickly and utterly repudiated? How does it feel to lose a million dollars in the process? "Painful," says Azenberg. "Painful in that the same effort was poured into it and didn't make it. The result wasn't satisfactory. What I felt was not felt by others."

Unlike some producers, Azenberg has no desire to make movies. "I'm 47 next year," he says. "I don't really have that ambition." His current plans include, besides the new Simon play, a London import called "Duet for One" and a prospective musical by lyricist Richard Maltby (the creator of "Ain't Misbehavin'") and composer David Shire. He will also bring the Twyla Tharp dance company to Washington and the National Theatre next fall.

Azenberg's first theater job, after his discharge from the Army in 1958, was a "go-fer" on a play that ran two nights. "If you would have asked me to be the producer, I'd have said, 'I don't know what they do,'" he says. "If you have told me I'd have 13 companies going at the same time . . . It's still a little mind-shattering. About 2 o'clock in the morning, there's a great ego explosion. But you do it in the privacy of your own room."