The Los Angeles Chamber Orchestra made its Washington debut at the Kennedy Center Saturday night, bringing along with it another face new to this city, that of the Russian emigre pianist, Bella Davidoich. Both are in the process of making themselves known to a wider audience, and the concert was an auspicious start to what one hopes will prove regular visits to this city.

The 51-year-old Davidovich (pronounced Da-vee-DOH-vitch) was a major soloist in the Soviet Union for more than two dozen years before leaving to join her son, a student at Julliard. She was first heard in this country last fall, shortly after her emigration, at a Carnegie Hall recital which generated considerable enthusiasm.

She brought an appealingly warm and intimate quality to her performance of Beethoven's first piano concerto with the Los Angeles Chamber Orchestra under Gerard Schwarz. Though her techincal command was quite solid, she charmed rather than overwhelmed the listener. There was no affectation of any kind, either musically or personally, simply a beautifully rounded tone applied with great clarity and musicality.

With an engaging lucidity she laid bare the evolution of each movement, displaying an elegant sense of line and, in the last movement, a playful streak well-suited to the music. Hers is an immensely accessible art, blessed with the gift simplicity.

Now in its 11th year, the Los Angeles Chamber Orchestra was taken over by Schwarz in 1979 when Neville Marriner left. Its current membership appears young and the ensemble performs with freshness and enthusiasm. Its playing can be quite precise, as evidenced by some crisp trilling and and particularly fine horn passage, in Handel's "Water Music Suite."

A major problem, however, was Schwarz' failure to set a strong, steady beat and, as a result, much of the music lacked a sense of rhythmic definition. Schwarz also could do much more in shaping phrases with these musicians. As their vibrant string playing in a Strauss piece and a series of lovely woodwind solos revealed,they are capable of a great deal.