Otis Ducker insists he entered the Prince George's school board race against the man who beat him four years ago because he is an "advocate for children"--an attribute he says is missing among current board members.

Ducker, 53, is challenging incumbent Angelo Castelli of Oxon Hill, who defeated him by 1,187 votes in 1978 for the District 8 seat. Ducker said he is back in the ring because he believes Castelli has been slack in his commitment to the education of the county's children.

"If I thought he was doing good job, why would I want to blow a good thing?" Ducker asked.

He is vying for one of three available seats on the nine-member board. In addition to Castelli's slot, board member A. James Golato of Bowie will vacate his 5th District seat to run for County Council. Lesley Kreimer of Greenbelt is unopposed for reelection in the 2nd District. The general election is Nov. 2.

A 20-year resident of Prince George's, Ducker, of Oxon Hill, has served as director of administrative services at the National Institutes of Health since 1974.

Although the school board must run a shrinking school system battered by massive budget cuts and the elimination of more than 400 teaching positions, Ducker said he wants to serve on it because "I believe in public education. We owe that to our young folk. They're our legacy.

"This is the time to become innovative and creative and look for ways to provide quality education despite the budget cuts," Ducker said.

Poor communication among the current board members has prevented them from establishing priorities for the school system, he said. One goal should be to save money in areas that are not directly education oriented. For example, Ducker said, the school system should share trash removal services and computer facilities with other county agencies, rather than maintaining its own.

Speaking from his plush, spacious NIH office, Ducker criticized the current board for being a "rubber stamp" when it approved this year's reduced school budget. The board, he said, received an eight-page document from Superintendent Edward J. Feeney and accepted it "carte blanche. I just feel the people of the 8th District deserve better."

Ducker said he could make a difference on the board because he would try to persuade the members to discuss issues, such as the budget, they he says they have avoided in the past. "I know with one vote you can't go in there and revolutionize the board. But I don't let it stop me from trying."

Emerson Markham of Camp Springs, who ran against Ducker in the 1978 school board primary and lost, now is one of Ducker's major supporters.

" Ducker will provide an integrative force on the board, which tends to splinter" into factions, Markham said.

Markham said Ducker works effectively with groups, noting that two years ago he worked with Ducker on the board's committee that developed a plan for removing 1,000 chidren from buses without upsetting the racial balance of the schools.

As a member of the Parent Teacher Student Association of the Cheltanham Center, a school for emotionally handicapped children, Ducker said he spent "untold hours" meeting with school and county administrators, school board members and members of the Maryland General Assembly in a successful effort to get the state to take over its operation. Ducker and his wife, Barbara, have a son, Anthony, 16, who attends Cheltenham.

School board member JoAnn Bell, who also was involved in the effort to persuade the state to assume control of Cheltanham, said Ducker did the "instrumental lobbying job in helping to secure the votes" for the passage of the bill.

She called Ducker a "caring, conscientious . . . task-oriented person."

Ducker condemned Castelli's proposal to expel any student found with drugs, alcohol or weapons. Instead, he said, punishment should be decided on a case-by-case basis. Castelli's suggestion, now being considered by the board, shows "political expedience as opposed to logic," Ducker charged. The board is scheduled to discuss the proposal at its next work session on Monday.

Ducker also criticized a budget-cutting proposal before the board to eliminate from the high school curriculum eight elective courses. He said their elimination would lessen students' chances of being competitive candidates for the "better universities."

Discussing the NAACP's suit against the county seeking to show that a court's 1972 desegration order has been neglected as the proportion of blacks in the county has grown, Ducker said he will abide by whatever decision is reached. "I believe in an integrated school system," he said.

Ducker said he is "not conducting a racist campaign. I don't run as a black candidate. I run as a candidate who is black." Bonnie Johns is the only black member of the current board.

He also said he would help the board take a more "proactive" stand on the issues confronting it. "It's a cop-out to make these noises from the sidelines," he said.