Some things about Maryland's Fourth Congressional District are constantly puzzling. For instance, Democratic voters here outnumber Republicans by three to one. So it would seem that the winner of the three-way Democratic primary race would have a good shot at victory in November.

It probably seemed that way in 1976, too. And in 1974. And in 1972. But in each of those years, incumbent Republican Rep. Marjorie Holt soundly trounced three strong and well-known Democratic opponents.

So the precinct captains in this district, which takes in all of Anne Arundel Country and a wide swatch of southeastern Prince George's, have stopped puzzling about it and become resigned to a paradoxical reality.

In the heavily Democratic Fourth district where watermen, farmers and suburbanites of two vie with residents of Annapolis for a representative's attention, Republican Holt reigns supreme.

Though diligent constituent service and a genteel manner that makes even the most reticent people pour their hears out to her, Holt has kept a tight hold on her congressional seat.

The three relatively unknown Democratic candidates who want to challenge Holt - Sue Ward, Brad McClanahan and John Griffin - know this. So, in their distinctive ways, they have devised campaign strategies to combat not only each other but also the incumbent's power and name recognition.

For Ward, who is considered by most observers to be the strongest candidate in the Sept. 12 primary election, the rate has always been "an uphill battle."

From December when she plowed through the snow of southern Prince George's to attend a senior citizens' meeting in Aquasco, to a mid-August candidate's forum in Harundale Mall near Glen Burnie. Ward has been the organizing force behind a well-orchestrated campaign aimed at building the name recognition of one Sue Ward.

With a cragg appeal reminiscent of Bette Davis, Ward elicits the personal determination of a party worker who for years has labored behind the scenes for other candidates.

Ward, 42-year-old social worker from Clinton, is straightfoward about the reason she is running in the Democratic primary. She said the record or her Republican opponent makes her "angry."

"I'm mad," she told a group of senior citizens recently. "I hear that the current congresswoman is running on her record in support of senior citizens rights. I just don't see that."

Ward is quick to point out Holt's voting record on bills involving senior citizens, energy, and tax reform. "She always votes for programs, then votes against the funding required to make the programs work," Ward said.

"Holt says she is a fiscal conservative yet she votes to spend hundred of millions of dollars on the breeder reactor, on defense projects. She may have voted more for the South and West than any other Easterner."

Holt, who recognizes Ward as the prime contender in the Democratic primary, said her own voting record shows she is effective."

"People want a representative who is generally concerned with them," Holt said. "And in my district I must reconcile the interests of all the people. Ward picked out certain amendments and certain bills that I had to vote against because I thought they were too costly. I have to support those things that will be good for the district."

Holt said she cannot respond to questions about her other two possible opponents because, she said, "Frankly, I haven't really heard or seen much f them."

Frank Bradlyn "Brad" McClanahan is running a very low-key campaign, according to observers. At a recent candidates' forum, McClanahan, a 27-year old businessman from Annapolis, offered as his qualifications his time spent "working with the elderly and with the young."

Repeated efforts to reach McClanahan to discuss his campaign, however, have failed. According to a voters questionnaire, he is running on a platform that includes restructuring of the tax system and on his "knowledge, understanding and compassion" as a "fellow working man."

Of the three candidates, he is the only one who has previously sought elective office. In 1974, he unsuccessfully ran for House of Delegates.

The third candidate, John Griffin, has been dubbed "the phantom" by his opponents and members of the Democratic party in the two counties.

A 39-year-old advertising executive, Griffin moved into the district, in May, filed for the House seat in June and then went to New Orleans for two months of duty in the U.S. Naval Reserves.

Griffin, however, takes his campaign very seriously. His strategy centers on a planned "last minute blitz," of newspaper advertising, direct mailings and personal appearances throughout the district.

Although new to the Seven area, he said he anticipatese "no difficulty in winning" the primary and said his experience as a media consultant in past presidential and congressional campaigns will make him "the least unknown of the three candidates on election day." "I know how to get the name across and make people remember it," he said recently.