You may not have heard of Rep. Ron Mottl--he's neither a giant in the House nor a regular on Washington's party circuit. In fact, he's never spent a weekend in Washington in his seven years in Congress.

"I love Cleveland," says Mottl, who actually lives in Parma, the suburb he represents. "Washington is a wonderful city to visit, it's a beautiful city, but I wouldn't want to live here."

So he doesn't. Until this summer, Mottl says he took a $35-a-night room at the Coronet Apartments on Capitol Hill. After the building closed in June, Mottl began spending his week nights on a fold-up cot he keeps in his Rayburn Building office.

But if you haven't heard of the Ohio Democrat, you might someday hear of his children, for Mottl may be the beginning of a political dynasty, Parma's answer to Joseph P. Kennedy. And you'll recognize his heirs since three of his four children share his name.

There's Ronald Jr., Rhonda and Ron Michael. The first two children are from a previous marriage; Ron Michael and another daughter, Amanda Leigh, are by his second wife, Debbi, a former campaign worker and babysitter for his children whom Mottl married 12 years ago when she was 18 and half his age. Debbi Mottl was adament that the fourth child not be another variation of her husband's first name.

"The reason I'd done that was in case my sons ever wanted to go into politics, they would have similar names to be identified with their dad," says Mottl. "It took me a long time to build up the name in Cuyahoga County."

Last year Junior, as Mottl calls his oldest son, made a losing bid for the Ohio State Senate. He was a 17-year-old high school student at the time.

"He was young, I'll grant you," says his proud father, "but he'd like to be governor of our state, and if you start real young, you can be governor of the state of Ohio in maybe your mid-30s."

Once, when a Cleveland television station arrived at Mottl's house to interview him about a veterans' issue, the congressman refused to do the interview unless his son, the candidate, be shown seated next to him. The reporter refused, but the camera happened to be running during the debate, and the exchange made that evening's news.

Rep. Mottl was displeased.

"It was unethical to tape me without my permission," he told a Cleveland newspaper. "I invited the reporter to my home, gave him a Pepsi and let him use my phone, and he reacted by being pushy. I know my strong points. A big one is the fact that I have an attractive family ... I like to have them on TV with me--I'm an ugly duckling."

Standing 6 feet 3 inches--not including the extra inch his brush-cut gray hair adds to his height--Mottl has the look and manner of an amiable baseball manager. Sporting polyester, he dresses like one, too. He likes to play basketball in the House gym and pitches for the House Democratic baseball team. (He calls the annual Democrats v. Republican game "one of the high social events of the year.)

His Rotarian image, however, is disputed by those who disagree with his politics. Mottl's two pet peeves: the imposition of low-cost subsidized housing in more affluent neighborhoods and mandatory busing to achieve racial integration in schools.

"Prehistoric man," snarls Cuyahoga County Democratic Party chairman Tim Hagen of his own party's congressman. Mottl faces redistricting problems next year, and Hagen makes it clear he won't miss Mottl if he should be redistricted into Lake Erie.

Democratic disenchantment with Mottl, heightened by his support of Reagan's budget cuts, led to news stories recently that Mottl would switch parties. He was obviously courted.

For example, 19-year-old Ronald Mottl Jr. was a candidate again last month, this time running as an independent for the presidency of the Parma City Council. In an unusual gesture, he was invited to meet along with his father, another Ronald--Reagan. The Mottls discussed with Reagan future sewer grants for Parma, Rep. Mottl's effort to gather enough signatures to force out of committee a bill forbidding busing, and a Justice Department fair housing suit against Parma. The meeting fueled the rumor that Mottl might become a Republican.

Mottl put that speculation to rest a couple of weeks ago when he rose on the floor of the House of Representatives to reassure his colleagues he would always remain a Democrat. There was a light smattering of applause.