IN ITS "TASK FORCE" plan for the District of Columbia, the Carter administration has gone and done precisely what this city needs least. With all the old familiar patronizing fanfare, the President has established yet another federally stacked layer of oversight through which legislative proposals affecting the community are to be studied, argued, grudgingly permitted or warped beyond recognition before anything at all is transmitted to Capitol Hill.

Thanks to the self-serving initiative of House District Committee Chairman Charles C. Diggs Jr. (D-Mich.), who sought the original White House session that led to this awful idea, any efforts to increase local self-determination here can be mothballed for now. Indeed, at this point the White House doesn't even seem to know what kind of deadlines the task force ought to try to meet. But you can get some estimate from the fact that it has taken more than six weeks since the White House meeting just to appoint - load, really - the task force.

Though administration staffers emphasized that no formal votes will be taken, it doesn't take a Gallup poll to figure out where the weight of this ad hoc colonial cabinet will rest: Seven of the 14 members just happen to be members of Congress. Then there are Vice President Mondale and four White House staff members. That leaves two slots for representatives of the local government, for the mayor and city council chairman. It also leaves 12 members of the elected city council somewhere else, apparently to make their views known some other way.

As if that weren't bad enough, nobody outside city hall seems to have even a vague idea of what, if any, priorities this new team ought to be setting. What about voting representation for the District of Columbia in Congress? Will the Carter administration support an earnest, immediate effort on Capitol Hill to pass the necessary bill - or not? Does the White House support an increased federal payment - or not? Will Mr. Carter support improved financing for Metro - or not?

Of course the answers to these questions involve specifies. But why does it take all this bureaucratic baggage to figure out what ought to be considered by Congress? Indeed, the city's true friends on Capitol Hill should be as insulted by this rigamarole as are the city council members. There's no need to suspend legislative efforts just because the White House can't figure out an agenda for the District. In the meantime, the task force ought to meet immediately and begin consideration of its demise as promptly as possible.At the rate things are going, even that is probably going to take too long.