He didn't expect to win. After all, how creative or original was it to adapt the red and white stars-and-bars design on the District of Columbia flag?

But James L. Moseley of Northwest decided to submit his sketch anyway. What the heck, he remembers thinking, it was only 20 cents worth of postage, anyway.

They were cents well spent. Last Friday morning, Moseley's design was officially unveiled as the one on which the city's new license plate will be modeled.

Moseley won a handshake from Mayor Marion Barry before the TV cameras, a certificate of appreciation from the city--and best of all, free tags for a year for his 1980 Dodge Omni.

"Yes, I've won things before," said the 34-year-old Moseley, who works the graveyard shift as a policeman at the Navy Annex in Arlington. "But I've never won anything quite like this."

The contest to choose a new city tag was conducted last fall by Jeff Hoffman, editor of City Hall New Times, a newspaper published by the District government. More than 200 people submitted entries. Moseley's red-white-and-blue sketch was chosen by a panel of five judges early last month.

The winning design looks a little like a candy cane laying on its side. The background is white. Along the top tier are three widely spaced red stars. Two horizontal red stripes run through the middle, with a much thinner white stripe separating them. Superimposed on the stripes are six numerals. They're in light blue.

Hoffman decided to run a license plate contest after some loose-fingered columnist named Levey crusaded on behalf of a new D.C. tag. The bicentennial was five years ago and counting, this protector of the local landscape wrote. While the D.C. plates being issued today don't say "Bicentennial" any more, about half the cars on the streets still have plates that do. So it was high time, no?

What that nugget of nudging got me was a seat on the judging panel. Chance to put your money where your mouth is, and all that.

But it was a chance that proved fascinating--and funny.

The tongue-in-cheek entries were delicious.

Richard Marchesano, an advertising man, submitted a design that featured a huge mushroom cloud. The slogan: "Washington D.C./One of the First Cities to Go."

More political was Clare Feinson of Northwest. Referring to Our Town's lack of voting rights, her slogan was: "Free the D.C. 700,000."

Julie Green of Charlottesville suggested as a slogan, "The Buck Starts Here." Karen Warmer of Northwest, tired of watching the city's budget get buffeted on Capitol Hill, suggested that the colors on the new plates be black and blue. Jean Gazeau of Northwest suggested as a motto for the plate, "The Little Apple." "Without Medfly, of course," she hastened to add.

But the top laugh-getter was the entry of Richard Green, an inmate at Lorton Reformatory. The slogan on his entry was "Washington, D.C./City of Justice." The digits on his design read: "I-KNOW-2."

The one piece of unfinished business is the wording on Moseley's design.

His entry has "Nation's Capital" across the top and "Washington, D.C." across the bottom, just like the current tags. Barry said Friday that one line or the other may be changed to something snappier before the plate goes into circulation, probably in March 1983. Barry's Committee to Promote D.C. will look into alternatives.

Meanwhile, James Moseley will do what he has been doing since he received a degree in art from the University of the District of Columbia: try to find a way to make a living as a commercial artist.

"I've done a lot of graphics as a free-lancer," he said. "But I haven't had things that have been very visible."

In about a year, James Moseley won't ever be able to say that again.