A NEW D.C. Council chairman and some other at-large and ward members will be chosen this year. In the contest for chairman, Council member John A. Wilson is the clear choice. His only challenger on the Democratic ballot is Vincent Orange, who has campaigned vigorously and seriously, but who is up against a most valuable council member. Mr. Wilson has been quick and strong in his warnings about the treacherous financial path that the city government was and still is following and consistent in his concerns for the interests of people of all income levels. All of Washington can vote for John Wilson with confidence that the council will be led by someone with a solid grasp of municipal finance from revenues to budget.

The Democratic primary contest for one at-large seat offers three able candidates with differing styles. Linda Cropp has served the school board and has a solid knowledge of the District government. Johnny Barnes, who has lived in every ward of the city and has been a longtime aide to Del. Walter Fauntroy, also has a full history of work on local issues. Terry Lynch has first-hand knowledge of social services, the problems of homeless and related issues, stemming from his active involvement in, and leadership of, religious and civic coalitions. Whoever wins this election will enter a second round, which includes independents, among them Marion Barry. That becomes a consideration in choosing a Democratic nominee. In terms of programs, ideas, legislative knowledge and ability to take on Mr. Barry, the edge goes to Mr. Barnes.

In Ward 1, incumbent Frank Smith has not exactly compiled a distinguished record of accomplishments. This year as last time, Richard M. Landis seeks to replace Mr. Smith. But though Mr. Landis has covered his territory energetically and can point to weakness in the ward representation, his own grasp of local issues is not always reassuring. Mr. Smith, at least, knows the job.

Ward 5 once again continues its frustrating tradition of weak representation, brought about because too many challengers divide the votes of those who seek change. This is how incumbent Harry L. Thomas Sr. is likely to win again. The situation this time in Ward 6 is similar, with incumbent Nadine Winter challenged by five candidates with only limited exposure to local public service. Of these Harold Brazil presents the best case for a new face from a new generation of professionals with a most welcome and healthy desire to serve their city government. Still, Mrs. Winter -- whose volatile style and often sudden switches on key votes can drive colleagues and constituents up walls -- has a remarkable Ward-Sixth sense of the city and its streets. Voters who value this quality will stick with Mrs. Winter. Those who want to encourage new, concerned professionals of all races to tackle the rigors of local government will find a willing example in Mr. Brazil.