CREATE TABLE table_73913 ("Outcome" TEXT, "No." TEXT, "Date" TEXT, "Championship" TEXT, "Surface" TEXT, "Opponent in the final" TEXT, "Score in the final" TEXT)

Andy Roddick is the opponent in the final on what surface?
SELECT "Surface" FROM table_73913 WHERE "Opponent in the final" = 'Andy Roddick'
SELECT "Surface" FROM "table_73913" WHERE "Opponent in the final" = 'Andy Roddick'