CREATE TABLE table_59331 ("Date" TEXT, "Tournament" TEXT, "Surface" TEXT, "Opponent" TEXT, "Score" TEXT)

What is Surface, when Opponent is 'Ji Van k'?
SELECT "Surface" FROM table_59331 WHERE "Opponent" = 'jiří vaněk'
SELECT "Surface" FROM "table_59331" WHERE "Opponent" = 'jiří vaněk'