Larry Pascal, the politician, is hoping that his record after next Tuesday's election will be better than that of Larry Pascal, the coach, who last season logged a 0-20 record coaching teen-aged basketball players.

"When I told the kids I couldn't be coach this year because I was running for public office," said Lawrence J. Pascal, the Democratic candidate in the contest for the 42nd District House of Delegates seat in Fairfax County, "they said, 'Mr. Pascal, that's the best news we've had in a long time.' "

What was good news for the basketball team, however, may have been bad news for the opposing Republican Party and its candidate, Robert K. Cunningham, in a campaign where the season is expected to end in a much closer match.

The campaign for the House seat in a district that sprawls from the suburban lawns of Springfield to Lorton Reformatory and the Fort Belvoir military reservation has been targeted by both parties as one of the most important legislative races in the state.

The Republicans consider the district crucial to maintaining their numbers in the Democratic-dominated General Assembly. It has been a GOP bastion since Stan Parris, now a U.S. representative, won the statehouse seat for his party in 1962.

The Democrats, meanwhile, see the race as an important chance to snatch back the seat that has been held by the powerful Republican delegate, Warren Barry, for the past 14 years.

Polls commissioned by Republicans and independent groups show conflicting results, some giving Cunningham, 61, a retired colonel with the U.S. Army, a wide margin of victory, others giving him a thin edge.

"The fact that I'm the underdog isn't a bit discouraging," said Pascal, 41, an attorney and a marathon runner who dons his running shoes each evening after work to make his door-knocking rounds. "I think they the Republicans are too smug."

"It would be a major coup for the Democrats to win and a real blow to the Republicans to lose," said one Republican party activist. "It's a very important race to both parties."

Both parties began gearing for a tough race when Barry announced he was giving up his seat to campaign for Fairfax County clerk of court. Although both Cunningham and Pascal are making their first bids for public office, Cunningham entered the race with a slight, but formidable, edge. As chairman of the 8th District Republican Committee, he has been managing Republican campaigns since 1976, including Linwood Holton for Senate, Stan Parris for Congress and Marshall Coleman for governor.

"Neither of us has a good name identification," admits Cunningham. "Republican activists know me very well, but that's not enough to win an election."

On the campaign trail, Cunningham stresses that what he lacks in name recognition, he more than compensates for in experience over his younger opponent.

"When I knock on doors, they don't ask about issues, they ask about experience," says Cunningham. "I say I'm a Republican, that I want to replace Warren Barry and I get almost zero questions on issues."

And on the issue of experience, Cunningham points to his long years in the military, which included a brief stint with the CIA, and notes, "I've been an adult twice as long as my opponent."

Pascal admits, "I'm new, I'm green" as a politician, but points to his 17 years as an attorney with the Alexandria firm of Ashcraft and Gerel, which specializes in workman's compensation cases. He says the job has prompted him to spend long hours in the state legislature as a lobbyist working with local delegates and senators: "I'm no stranger to the General Assembly."

And Pascal disputes Cunningham's contention that voters in the district aren't interested in issues. "Transportation is the first thing on their minds--they say they can't take the traffic jams any more."

Pascal's campaign platform includes proposals for the creation of a special math and sciences high school in Fairfax County to make Virginia more competitive in recruiting high technology industries as well as a proposal giving Virginia businessmen a slight advantage in awarding state contracts for goods and services.

The two candidates also have taken opposite approaches in running their campaigns. Cunningham takes advantage of the machinery he has helped oil for years, and Pascal counts on his enthusiasm and energy to push him over the top at the polls.

Cunningham, who labels himself a "team player" after years of managing other campaigns, is running a campaign that emphasizes Cunningham the Republican, rather than Cunningham the candidate.

In fact, his personal views are blurred frequently by the views of those he has represented over the past few years. When asked about specific issues, he usually quotes a position taken in the past by one of his fellow Republicans.

"The least we can do is keep Barry's seat Republican," says Cunningham, adding, "When Barry decided he wouldn't run, several other Republicans said . . . I'd have as good a chance as anybody keeping this seat in the Republican column."

Cunningham's military and campaign background is reflected in the precision with which he runs his campaign. On his desk are stacks of computer-printed cards, the voting records of every resident in his district who has voted since 1981: "If they didn't vote in 1981 or 1982, I'm not going to fool with them."

Campaign volunteers manning phone banks telephone the names on the cards. Each call is followed up by a letter appealing for their vote.

While Pascal has high school students operating his telephone banks, he has based his campaign style on personal contact. He is striving with a dogged determination to knock on the door of almost every resident in the 42nd district, a goal he admits he probably won't meet before election day Nov. 8.

"I think we'll win if I can just get to the voters and reach enough people," says Pascal.