Henry E. Howell and Andrew P. Miller today debated each other for the first time in their contest for the Democratic nomination for governor of Virginia, and promised a significant increase in the number of blacks and women in state government jobs.

The 90 minute exchange in a Richmond school was sponsored by the Democratic Black Caucus of Virginia. The caucus, one of the two principal black political organizations in the state, met after the debate but decided not to endorse a candidate at this time.

For the first time in Virginia, blacks, who make up more than 18 per cent of the state's population, have high expectations of a major stake in a Democratic administration regardless of who wins the primary.

Both Miller and Howell have given campaign jobs to blacks and are seriously contesting for the black vote.

In answer to questions by four reporters, Howell and Miller stressed their records as advocates of a larger role for blacks in Virginia.

"I have fought with more vigor and commitment than anyone else running to bring fair treatment to all people of Virginia," Howell said. "I first ran for office because of massive resistance (by the Virginia government to school desegregation.) I helped produce the first integrated ticket for the House of Delegates from Norfolk."

Miller cited his record as state attorney general from 1970 until last month. "I was the first attorney general of Virginia to put blacks and woman in professional jobs," he said, "and I was the first Southern attorney general to enforce the voting rights act."

Neither candidate set specific targets for placing women and blacks in policymaking positions. Miller said, "We have got to move beyond tokenism in this. I will wage an aggressive recruitment campaign."

Howell said, "Women and blacks will be helping Henry Howell to be governor."

Throughout the debate, the two candidates, both lawyers and experienced public officials, demonstrated only minor differences of opinion on issues but a sharp contrast in style. Miller made his points in a studied manner, Howell often with the colloquial style that marked his successful campaign for lieutenant governor in 1971, and two losing bids for governor in 1969 and 1973.

For example, when asked to put a political label on themselves, Miller called himself a "responsible progressive." Howell said, "Just say I believe in life after birth" - and old saw of moderate-liberal Democrats in Virginia who used it to imply that the dominant conservative wing of the partly did not.

Howell and Miller both have pledged to avoid the bitterness that has split Democrats during the past 10 years, but neither resisted opportunities to take dig sat the other day.

When Miller claimed credit for initating a non-disciminatory test intended to increase the number of black state troopers, Howell said, "He was attorney general for seven years and now he tells us he will have a test next year."

Miller chided Howell for saying, "All is fair in love, war and politics," and said he hopes Virginia will never again witness what he implied was a campaign of distortion waged in 1972 by U.S. Sen. William L. Scott (R) against former Democratic Sen. William B. Spong.

Then, as if warning that it may happened again in this race, Miller said, "I understand that Mr. Howell has hired an advertising agency that engages in negative-image campaigns."

Howell did not respond, but his campaign manager, Paul Goldman, said after the debate that Howell's organization has not yet hired an advertising agency.

The two candidates also sparred over their respective records as consumer advocates.

Howell has made consumer advocacy, especially against electricity and telephone companies, a central feature of his political career. He recalled that he once won a refund of more than $4 million for customers of the Chesapeake & Potomac Telephone Co. in an appeal of a State Corporation Commission award.

Recalling his criticism of the three-member SCC in the late 1960s and early 1970s. Howell told the crowd of about 100, "I made it so difficult for the three elderly gentlemen on that commission that one went to heaven and the other went into retirement."