YEILDING UNWISELY to tenant pressures, the District Council has enacted a 90-day halt on nearly all condominium conversions in the city. It is an evasion that helps no one except the council members, who weren't up to the challenge of supporting serious housing legislation. Just as they had once turned desperately to politically expedient and economically unrealistic rent controls as apalliative for injured and angry tenants, so the council members have grasped at yet another condominium moratorium; and as long-term policy, it would be just as unrealistic and undesirable for tenants.

The latest measure freezes conversion of nearly 10,000 units. During the 90-day delay, there is to be creacted - what else? - a study commission to ptopose permanent laws. You would think local legislators had neven seen the condominium controversy before - even though "condo" has been a trigger word here for years.

More than 20 percent of the initial conversions in the United States took place in this metropolitan area. Then as now, thousands of tenants in the region - many of them older people to whom the shock of displacement can be financially as well as mentally ruinous - have been forced to compete for a fast-shrinking supply of reasonably priced rental units. The BandAid response of local officials was the temporary moratorium - buying time but resolve nothing.

Three years ago the District did take one constructive step. The council approved a compromise bill that regulated but did not prevent conversion. It helped to preserve rental units and assisted displaced tenants. The law allowed unrestricted conversion of higher-rent housing, but permitted conversion of other properties only if the citywide cavancy rate for this category was more than 3 percent, or if a majority of tenants agreed to a conversion. This measure also contained an important relocation assistance provision, requiring that developers provide moving expenses for low-to-moderate-income tenants evicted because of conversions, and financial assistance for two years to help meet higher costs of new housing and for those still eligible, payments from thecity hereafter.

All of this was sensible. But now the same kind of thinking should be extended to higher-rental units, too, along with other assistance provisions that could ease some of the traumatic consequences for tenants. For example, in Montgomery County - where a moratorium has just been rejected - there is pending legislation that would allow the county or tenants themselves, acting as a coversion. This proposal also would give renters first-refusal rights on condominium purchases. In the District, conditional permits could include some form of "grandmother" clause reporting that elderly residents be allowed to stay on and make payments for their units without meeting downpayments.

For poorer tenants, assistance must be a public responsibility, for it is neither realistic nor fair to except property owners to absorb the impact of rent controls and inflation in a tight housing market.