Three incumbents and six newcomers will vie for six positions on the Democratic ticket for Alexandria City Council during a primary tomorrow.

Voters also are expected to endorse Patricia S. Ticer, who is running unopposed for the party's nomination for mayor, to lead the Democratic ticket in the May 7 election. Ticer, 55, likely will face Republican Ann Stone, 38, in a campaign expected to center on the issues of development, education and city finances. The race will mark the first time two women have competed for the city's highest elective office.

Balloting for the nine candidates will be held from 4 to 8 p.m. at the Howard Administration Building, 3801 W. Braddock Rd. Participants must be registered Alexandria voters and must sign a pledge indicating they are Democrats and will support the party's candidates.

Incumbents seeking endorsement by the party are council members Kerry J. Donley, T. Michael Jackson and Redella S. "Del" Pepper. The newcomers are:

Kris Balderston, 35, an international trade consultant and a Del Ray Civic Association leader.

Barbara Harris, 48, a certified paralegal and city NAACP official.

Lonnie Rich, 43, a lawyer and board member with the North Ridge Civic Association.

Stan Vosper, Jr., 41, a real estate broker who has lived in the city 35 years.

Glen Wright, 44, a senior planning administrator.

Lynnwood Campbell, 43, a certified public accountant who serves on the School Board, is seeking the party's endorsement as an independent. Carl Alexander, a West End resident and prosecutor with the Justice Department, also is running as an independent, but has not asked to be included in the Saturday vote, Democratic leaders said.

The Republicans, who will hold a similar primary Feb. 23, are expected to make a strong push this year to reestablish themselves in a city that has been dominated by Democrats this century. The Democrats gained a 6 to 1 majority on the council during the last election and the city has not had a Republican mayor since Reconstruction.

Buoyed by past success, Democrats say they are confident, while Republicans, hoping for an anti-incumbent voter backlash, are expected to sound a theme that the city needs a viable two-party system.

"I think it's our strongest field of candidates ever," said Myke Reid, chairman of the Democratic Party, noting that his party has kept in step with the wishes of the voters. "We are hoping for a sweep."

Stone, 38, who owns a direct mail and marketing firm, disagreed. "There are a lot of Democrats who are dissatisfied," she said. "People feel like it has been a closed system."