WITH NEW responsibilities being placed on state legislatures everywhere, the candidates for the Maryland General Assembly and the Virginia legislature deserve close attention.

In Maryland, delegations from this region have gained respect and influence. From Montgomery in particular, incumbents are running whose leadership could be pivotal in budget, tax and services questions. They have helped protect the county from unfair overtaxation and curtailment of state assistance.

The right-hand man to the House speaker is Majority Leader Donald B. Robertson of Montgomery. He and three 18th District running mates -- Sen. Margaret Schweinhaut and Dels. Helen Koss and Patricia Sher -- have served more than a total of 55 years, gaining key positions. Del. Lucille Maurer in the 19th also has a long record of dedicated service. Laurence Levitan is the powerful chairman of the budget and taxation committee in the state Senate.

From Prince George's, State Sens. Thomas V. (Mike) Miller and Tommie Broadwater and Del. Timothy S. Maloney have used their experience and alliances well in the state capital, where the allocation of aid has been critical to the county's TRIM- crimped revenue picture.

Among area Republicans known for their concern and hard work, Sen. Howard A. Denis would be the ranking minority member, and Del. Constance Morella has worked closely with the regional delegation.

In Northern Virginia, meanwhile, legislators have also gained seniority and influence -- useful at a time when regional issues include continued state support for Metro and for other appropriations to offset federal cuts. Since Northern Virginia gives more than its gets back in the state budget, representatives from this area must press for equitable payments from Richmond for schools, roads and social programs.

Vestiges of the old rural-urban-suburban factionalism are still found in Richmond, but the Northern Virginia delegation has worked well with the top leadership in the House of Delegates and has its own Adelard Brault in the Senate leadership. Mary Marshall, James Almand, Warren Stambaugh, Marian Van Landingham, minority leader Vincent Callahan, Gladys Keating, Dorothy McDiarmid, James Dillard and Vivian Watts have all served the area effectively. Given the strict limits on local home rule in Virginia, the need for such legislators is all the greater as the legislature prepares to determine the state's responses to federal fiscal constraints.