What is Tournament, when Opponent In The Final is "Andre Agassi"?
CREATE TABLE "singles_23_15_8" (
  "outcome" text,
  "date" text,
  "tournament" text,
  "surface" text,
  "opponent_in_the_final" text,
  "score_in_the_final" text
);
SELECT "tournament" FROM "singles_23_15_8" WHERE "opponent_in_the_final"='andre agassi';