WHILE I WAS in New York for a short time last April, I noticed some billposters up near Columbia University on the upper West Side, advertising Jimmy McGriff and Junior Parker, who were playing a club called The Third Phase. Nobody I knew had heard of either Junior Parker or the Third Phase, so I went by myself and found a basement club, done up like a grotto in some sort of white polystyrene. Four or five student-type girls seemed to be running the place; and along with the five musicians on stage, they outnumbered the audience two-to-one. In the two hours I was there, maybe as many as ten people came in to see the show.