CLASSICAL Ravel, Maurice: Concerto in D for the Left Hand. Alborada del Gracioso. Rhapsodie Espagnole. Leon Fleisher, piano. Baltimore Symphony Orchestra, Sergiu Comissiona, conductor. (Vanguard Audiophile VA 25014.) This is Leon Fleisher's first recording in years, and by definition, it constitutes an event. The legendary pianist only recently returned to the concert stage, playing with both hands, though here he plays the Ravel Left Hand Concerto that he has performed on and off for many years. It is a splendid account of the concerto, lovingly accompanied by Sergiu Comissiona, a record that will give Fleisher fans much pleasure. On the other side of this disk, the two purely orchestral pieces are given the sort of performances we have come to expect from maestro Comissiona - thoughtful, superbly balanced, expertly shaped, iridescently detailed, slightly cool yet tense. The sound is a tad boxy, but one gets used to it very quickly. Vanguard's Audiophile series presents a handsome product in superior pressings.