Leaders of both major political parties in Virginia had a chance to exercise eloquence in defense of their party yesterday during the second round of debate on a bill that would change the control of the boards that run state and local elections from the Republicans to the Democrats.

Although the measure was finally approved by the Senate Privileges and Elections Committee on a 10 to 6 vote with one abstention it was not without enough hemming and hawing to create doubt about the eventual outcome. This is despite the fact that the legislature has only 26 Republicans among its 140 members.

The law now says that two of the three members on local electoral boards, who are appointed by circuit court judges, shall be from the party that received the most votes in the most recent gubernatorial election. Republicans have been winning the statehouse since 1969.

As proposed by Senate Majority Leader Adelard L. Brault, the majority on the board would come from the party getting the most votes in the preceding general election - and the Democrats still dominate the legislature. Brault contends that since they control the General Assembly, the Democrats are the majority party.

But Minority Leader William A. Truban was not about to let him get away with that.

"You have not carried this state in a presidential election for a decade," he told the Democrats on the Privileges and Elections Committee, "You have lost the governor's race the last three times; you have only four seats in the Congress. In the U.S. Senate, there is one Republican and one who is beholden to neither party. It appears to me it is a delusion for either party to say they have majority status."

Truban said the Democrats need to learn to be "good losers", and referred to the hard job he had ahead in getting the measure rejected.

"When you're out numbered 14 to 1 (in this committee) like I am, your best weapon is a pair of good legs for running, a room to jump in and hide, or kindness on the part of your adversary, or the Almighty. I could use all four."

Brault started out with all 35 Democrats in the Senate signing on as copatrons of the bill, but it appeared yesterday that some either were affected by Truban's oratory or were having second thoughts.

Sen. Hunter B. Andrews (D-Hampton) said "this bill is as political as hell . . . I am persuaded we are not the majority party in Virginia . . . this bill would never have been introduced if we had won in November." Andrews proposed an amendment that would have delayed the change until the 1982 elections.

His amendment failed by a vote of 7 to 8; Andrews later abstained on the final vote.

Brault says Republican Gov. John N. Dalton will probably veto the bill, and he wants it voted on quickly enough so that the General Assembly can override that veto.

The intent of the provision, Brault said, is to give "majority representation (on the electoral boards) to the political party dominant in the commonwealth . . . When you look at the members of the General Assembly and see by what large margins we have representation I just don't see how you can say the Democratic Party is not dominant."

Later, Brault, said that since there were so few Republicans in the General Assembly it was easy for them to "marshall their forces" and have speeches prepared for yesterday's hearing, which caused Truban to sputter angrily. "I'm so mad at him for saying that," Truban said after the meeting was adjourned. "I wrote that speech myself. Look, here are my hand-written notes. I'm really mad about this whole thing."