Which Score in the final has a Surface of hard on august 20, 1989?
CREATE TABLE "doubles_champion_12" (
  "outcome" text,
  "date" text,
  "tournament" text,
  "surface" text,
  "partner" text,
  "opponents_in_the_final" text,
  "score_in_the_final" text
);
SELECT "score_in_the_final" FROM "doubles_champion_12" WHERE "surface"='hard' AND "date"='august 20, 1989';