Rep. Louis Stokes (D-Ohio), on trial in Montgomery County Circuit Court on drunk driving charges, took the stand in his own defense for more than three hours yesterday, arguing he was sober when stopped by county police in Wheaton at 2:15 a.m. last March 25.

The 58-year-old chairman of the House ethics committee told the jurors he had worked long and hard the day before his arrest and was extremely tired but completely sober. He described the incident as humiliating and subsequent accusations that he was hiding behind congressional immunity as degrading.

"It was embarrassing," he said of the roadside sobriety tests officers had him take. "It was humiliating--a U.S. congressman standing up in the middle of the street at 2:15 in the morning with two police officers, not knowing who was passsing by. . . . It was a demeaning experience."

Stokes was released by county police about an hour after his arrest, officers testified during the trial, because they believed he enjoyed congressional immunity. Three weeks later, he was charged with driving while intoxicated, running a red light, and driving on the wrong side of the road. The last charge was dropped earlier in the trial.

Yesterday, the congressman denied failing the three roadside sobriety tests. He said he was confident he recited the alphabet properly, walked a straight line correctly and managed to touch both fingers to his nose.

Two officers testified earlier in the trial that Stokes missed the letters J and L and stopped at W when he was saying the alphabet and wavered off the straight line. One officer said he missed his nose, and another said he touched it with the base of his finger rather than the tip.

Stokes agreed he drove on the wrong side of the median strip on Randolph Road and had gone through a red light, but said: "I was of the opinion that what happened there was not a traffic violation." He said he had accidentally turned onto the wrong side of Randolph Road, quickly realized his mistake and corrected it. He said he believed that was "something that the law permitted."

Stokes said he stopped at the red light for about half a minute, and, believing it was stuck, drove through it and made a U turn to the correct side of Randolph Road. He said he "didn't feel that was a violation."

Stokes testified he had drunk one glass--about 3 ounces--of Almaden Mountain White Chablis in his congressional office between 12.15 a.m. and 12:45 a.m. while he was finishing paperwork, and then went to the nearby Hyatt Regency on Capitol Hill to try to get something to eat before going home.

The restaurant had already closed, he said, and he had a second glass of white wine in the hotel bar. In testimony Thursday, the hotel bartender agreed that Stokes had had only one glass of wine, and said he appeared sober. Stokes said he headed for home in Silver Spring, filled his car with gasoline in Wheaton and decided to drop by a nearby restaurant when he was stopped.

"I was tired," he said. "I had been on my feet since 5:30 that morning. I had not had any sleep and I had been going steady all the time." He said he was allergic to pollen, which sometimes makes his eyes red and watery, and that his eyes were bothering him. He said he was "more tired than I had been in a long time," and that he was "extremely hungry." He insisted that he was neither intoxicated nor impaired.

Stokes acknowledged under cross-examination by prosecutor Robert Greenberg that he had told reporters at two press conferences that he had had nothing to drink the night of his arrest and violated no traffic rules.

"The media was depicting me as a drunk--a lawmaker who had broken the law himself," Stokes said. . . . The press had gone wild without any knowledge of what I had been drinking. . . . I wasn't about to give them anything else to further degrade me."

The trial is expected to conclude Monday.