What is the total outcome for the clay surface on April 21, 1996?
CREATE TABLE "singles_14_12_2" (
  "outcome" text,
  "date" text,
  "tournament" text,
  "surface" text,
  "opponent_in_the_final" text,
  "score_in_the_final" text
);
SELECT "outcome" FROM "singles_14_12_2" WHERE "surface"='clay' AND "date"='april 21, 1996';