Gubernatorial candidate Charles S. Robb led other Democrats to a resounding victory at the polls in Alexandria's T.C. Williams High School Tuesday.

The senior class' mock election, in which 503 seniors cast their ballots on a voting machine, produced the following results:

Governor: Democrat Robb, 284 votes; Republican J. Marshall Coleman, 155 votes; Lieutenant Governor: Democrat Richard J. Davis, 228 votes; Republican Nathan H. Miller, 186 votes; Attorney General: Democrat Gerald L. Baliles, 241 votes; Republican Wyatt B. Durrette, 174 votes.

In the 21st District House of Delegates (two seats): Democrat Bernard S. Cohen, 242 votes, Democrat Marian Van Landingham, 206 votes; Republican David Speck, 169 votes, Republican Betty McCann, 130 votes.

"There's been more interest in the local election at the school than I've seen in the past," said John Porter, associate principal.

All four of the House of Delegates candidates had appeared at an assembly of seniors at T.C. Williams last week to speak and answer questions. A few of the seniors are 18 years old and thus eligible to vote in the general election. Among topics discussed by the candidates were the drinking-age bill, how the incumbents had voted on certain issues and how the legislature works.

Other area high schools are also planning mock elections. McLean High School seniors will vote tomorrow in their government classes for various state offices. And at Robert E. Lee High School in Springfield, 1,800 students will mark election day, Nov. 3, by casting their mock ballots during their lunch periods.