It was getting on toward midnight at the Annapolis Hilton bar, one of this political town's premier watering holes. The piano man had just finished a spunky version of "Hail to the Redskins," a song that just days before had moved Del. Gerard F. Devlin of Bowie to display a Mexican hat dance around the bar.

The blond guest crooner had taken a break, refocusing on her drink and her drinking mates around the piano. Lobbyists for utilities, banks and insurance companies authoritatively snapped their fingers to order drinks for yet another tableful of legislators.

Kay G. Bienen had made this scene dozens of times during her eight years as a delegate from Laurel, on some nights even replacing the crooner at the piano. Now, without a seat to occupy in the new legislature (she lost for state Senate in November), you might expect Beinen to abandon her old haunts. But this night, like many others, she appeared before closing time, sidling up to the bar with some legislator friends, her smoky voice filling the quiet just as it has done for the last eight years.

There are many similar scenes in Annapolis these days, as former legislators return to watch from the sidelines while a new General Assembly meets for the first session of a four-year term.

Some, such as Beinen and another Hilton occasional, former Senate minority leader Edward J. Mason, lost races that would have brought them back here. Others tried for different offices, some with success. A few left rather than face possible defeat or because they were simply tired of it all.

Yet, whatever the reason for the exit, most return to the old haunts and many, including past speakers of the House, return as lobbyists. Some, such as former delegates Charles S. Blumenthal and Robin Ficker, come back with press credentials--much to the concern of the politicians who beat them. Others return without portfolio, simply to watch those who won with a mixture of envy, regret and, in a few cases, relief.

You could see all those feelings in Luiz Simmons' eyes as he sat, one recent evening, in the most famous of Annapolis' drinking joints, Fran O'Brien's.

Simmons, a Montgomery County delegate elected to the legislature in 1978 and then unwillingly retired from politics last September when he ran unsuccesfully in the primary for Montgomery County executive, had spent many nights at Fran's.

Twice during his freshman year in 1979, others more experienced in the ways of the General Assembly had threatened to knock out his teeth right in front of the bar over legislation Simmons was proposing, he recalled.

"I wouldn't want to be back here, but I got to admit this was a helluva good time," said Simmons, watching a former colleague (now state senator) put the moves on a waitress. "This was the college fun I never had."

Simmons, who once envisioned an unstoppable upward curve in his political career, has returned to Annapolis this year as a lobbyist for the state's physical therapists. He admits it made him a little queasy the first time he reentered Fran's.

In the same bar, past the booming rock band, scores of dancers and round tables covered in white linen, Torrey C. Brown, once head of the House Environmental Matters Committee, is drinking with his former colleagues. Brown, unseated for reelection last fall, is back in Annapolis with some regularity these days. One of his prime focuses these days is to convince Gov. Harry Hughes to appoint him secretary of natural resources.

Another Fran's regular, John R. Hargreaves, who for more than a decade until his defeat this fall presided over the powerful House Appropriations Committee, also is hoping to return to Annapolis through an appointment. He tried unsuccessfully to become state treasurer and now, when asked what he would like to get appointed to, Hargreaves, smiling, says, "Got any ideas? I've thought about opening a knitting shop here."

Hargreaves, who spent 16 years in the House of Delegates, may have had the hardest transition into private life. For weeks he delayed giving up his lavish legislative office to the new committee chairman (and friend) R. Clayton Mitchell Jr. Then, with all his legislator friends (and friends of Mitchell) encouraging him, he took a long vacation, the only reason for his absence of late from the Annapolis bars.

"They don't want to be forgotten," said Sen. Laurence Levitan (D-Montgomery), who recently spent much of an evening at Fran's eyeing a pile of former legislators. "Guys like Torrey Brown, they like Annapolis. They like the scene. It gets in your blood and it's hard to get over it. I expect even old reporters come down here once in awhile."