When he was a high school student in California, Michael O'Harro chose his college (the University of Arizona) because he heard it offered a good time. "I majored in partying," O'Harro says. At age 37, he still hasn't changed majors.

When Twyla Littleton was 20 years old, O'Harro spotted her at a party, asked her out and today, a year and a half later, she is the first person who has made resolute bachelor O'Harro consider marriage.

Together O'Harro and Littleton are Washington's undisputed Disco Couple, sleek and, at least in O'Harro's case, rich. She is Miss Maryland, he is the brains behind the discotheque Tramp's, a pleasant room that looks like a rich man's library tucked inside Billy Martin's Carriage House. O'Harro, who earns about $85,000 annually from his disco, can't dance, a detail that doesn't bother him in the least; he leaves that to Twyla. Miss Littleton, who lives with her parents in Oxon Hill, leaves what she hopes will be a career in modeling and movies in the hands of the very-promotion-minded O'Harro.

"We complement each other," says O'Harro, who seems slightly awed by the fact he has dated the same woman for nearly two years. As one of Washington's early single bar owners (Gentleman II, Beowolf, My Mother's Place), he has met his share of women. And he is familiar with the beauty pageant circuit (courtesy of his friend and pageant manager, Sid Sussman) which allows O'Harro to populate his club with comely women who, in turn, attract men who buy drinks.

Twyla Littleton, a student at Prince George's County Community College, hopes for an acting career. O'Harro says wherever she goes, he's likely to follow. She is, he says, the "best example of the quality type of person who goes to discos - attractive and fashionable." Could a disco king ask for more?