CREATE TABLE table_30388 ("Outcome" TEXT, "Year" FLOAT, "Championship" TEXT, "Surface" TEXT, "Partner" TEXT, "Opponents in the final" TEXT, "Score in the final" TEXT)

Who was Betty's partner when the surface is hard?
SELECT "Partner" FROM table_30388 WHERE "Surface" = 'Hard'
SELECT "Partner" FROM "table_30388" WHERE "Surface" = 'Hard'