Who: Jonathan Katz, newspaper editor.

What: Annual convention, American Society of Newspaper Editors. (Katz attended last year joking about looking for a new job. This year he's editor of the Baltimore News-American.)

Where: Washington Sheraton. (In a room full of sizzling hors d'oeuvers and the nation's top newsroom nabobs.)

When: Last night. (But it was only the beginning. The convention goes on all week.)

And last, but not least, why?

"Why?" said Katz."Let's ask the real question: is there any difference between a shoe salesman's convention and a newspaper editor's convention?

"And the answer is -- no."

Likely story. Put the chiefs of the nation's newsroom together in one cavernous banquet hall and they may not talk about shoes, but that's just about the only thing that won't come up.

"Remember," said Seymour Topping, managing editor of The New York Times, "this is the most important gathering of journalistic experience that takes place in this country."

Like most important things, the reception began sedately, with handshakes and the requisite inspection of name tags (new society members sported red stars). But once the band got going, things loosened up and soon editors were speaking loudly into each other's ears.

"I come down every year now just to see the old-timers," said William Crouse, retired managing editor of The Woonsocket (R.I.) Call. "I've been to four White House receptions -- one with LBJ, two with Nixon, one with Ford and none with Carter."

None with Carter?

"Nope. He never had one."

The White House reception tonight will be just one attraction in a week that will include speeches by Secretary of State Haig and Vice President Bush. But, of course, 1600 Pennsylvania Avenue lures some more than others.

"Going to the White House tomorrow?" John McMeel (Universal Press Syndicate) asked Katz.

"Why would anyone go to that?" came the response.

"Hey," said McMeel, "I'm from Kansas."

According to veterans, the ASNE convention is always a mixture of business and socializing. "Sure, some guys come to do some work. It's about 50-50," said Norman Isaacs, the chairman of the National News Council.

It's also a good time for gathering inside information. "I was at a party with Walter Mondale last night, "said Topping. "I talked to him and gained some insight into his press coverage."

Such as?

"He's not getting any."

He may not be, but in a room full of newspapermen, the Janet Cooke Pulitzer Prize incident surely was.

"It's Topic A," said Lexington (Ky.) Herald editor John Carroll. "We may even be getting a little sick of it by now."

"God, I don't like to talk about it," said Steve Wilson, editor or Lexington's afternoon paper."It's like talking about a member of the family who died."

"It's not yet run its course," said Boston Globe editor Thomas Winship, outgoing president of the society. "It was a fluke -- could have happened in any newspaper in America. It just happened to occur in the goldfish bowl."