CREATE TABLE table_39056 ("Outcome" TEXT, "Date" TEXT, "Tournament" TEXT, "Surface" TEXT, "Partner" TEXT, "Opponent" TEXT, "Score" TEXT)

What person was played against when the playing surface was hard?
SELECT "Opponent" FROM table_39056 WHERE "Surface" = 'hard'
SELECT "Opponent" FROM "table_39056" WHERE "Surface" = 'hard'