CREATE TABLE table_45728 ("Outcome" TEXT, "Date" TEXT, "Tournament" TEXT, "Surface" TEXT, "Partner" TEXT, "Opponents in the final" TEXT, "Score in the final" TEXT)

Which Score in the final has a Surface of hard on august 20, 1989?
SELECT "Score in the final" FROM table_45728 WHERE "Surface" = 'hard' AND "Date" = 'august 20, 1989'
SELECT "Score in the final" FROM "table_45728" WHERE "Date" = 'august 20, 1989' AND "Surface" = 'hard'