Three men are vying for the lieutenant governor's nomination in Tuesday's Democratic primary. Two are members of the House of Delegates, the third a relative newcomer o the Virginia political scene.

Although the job is only part time and pays $10,500 a year, competition for it has been spirited because it is considered a stepping stone to higher office, particularly the governorship or a U.S. Senate seat.

The main function of the lieutenant governor is to preside over the Senate while the General Assembly is in its annual session, which essentially requires a knowledge of parliamentary procedure and the ability to stand on one's feet for several hours a day.

The lieutenant governor is also first in line to succeed the governor should he be unable to serve for any reason, until another election can be held.

The candidates, in alphabetical order, are: Ira M. Lechner, Richard S. (Major) Reynolds and Charles S. Robb.

Ira M. Lechner, 43, a member of the House of Delegates since 1974 representing Arlington and Alexandria. Before that he was chairman of the Arlington Tenant-Landlord Commission and active in state and local politics.

Born in New York City, Lechner attended Randolph-Macon College and Yale University Law School. He is a member of the firm of Roman, Lechner and Siefman in Vienna and Washington.

Lechner was state vice chairman of Henry E. Howell's unsuccessful campaign for the gubernatorial nomination in 1969 and worked later for the Democratic slate after Howell's defeat. He was campaign manager of Joseph S. Wholey's election to the Arlington County Board, campaign director for Armstead L. Boothe's unsuccessful senatorial race in 1966 and state campaign chairman for presidential contender Eugene McCarthy in 1968.

As lieutenant governor, Lechner said he would take an active role as an advocate of issues important to Virginia on a national level and work to influence legislation in the General Assembly. He said he particularly favors mandatory sentences for repeat felons, increased education for handicapped children and bargaining rights for teachers and other public employees.

He is married to the former Susan Schwartz, who is senior editor of the "It's Academic" television show.

Richard S. (Major) Reynolds, 43, a member of the House of Delegates since 1976, representing Richmond. He was a bachelor of arts degree in history. He has been active in state party politics, working in campaigns for his late brother, Lt. Gov. J. Sargeant Reynolds, and serving as an alternate delegate to the 1972 Democratic national convention and as a delegate to the 1976 convention.

Reynolds said his first responsibility as lieutenant governor would be to attract industry to Virginia in order to create more jobs. He also said that he would fight for a society "that exudes fairness, justice and opportunity for all."

He is married to the former Pamela Coe, who was a consultant to former Secretary of the Interior Rogers C.B. Morton.

Charles S. Robb, 37, an attorney from McLean who is currently on leave from the Washington firm of Williams and Connolly. He has been active in local and state politics since 1974 and was a law clerk to a U.S. Court of Appeals judge in Richmond and is vice president/director of the LBJ Co., the family broadcasting firm of the late President, Lyndon B. Johnson.

Born in Phoenix, Ariz., Robb graduated from the University of Wisconsin and earned his law degree from the University of Virginia in 1973. He is a member of the Virginia State Central Committee of the Democratic Party, was a delegate to the state convention in 1976 and served as deputy counsel to the platform committee at the 1976 national convention.

As lieutenant governor, Robb said he would function as an ombudsman for citizens and local governments with state agencies. He also said that attracting industry to the state is a top priority, as well as the promotion of tourism.

Robb advocates "the streamlining and reorganization" of state government, opening the budget process to citizens, the development of programs for and the elimination of mandatory retirement age requirements for state elderly employees, the creation of an "Oil Spill Strike Force" to act quickly on such disasters and the expansion of Virginia's seaports.

He is married to the former Lynda Bird Johnson, a free-lance writer who is also active with the Reading is Fundamental group.