CREATE TABLE table_15618 ("Year" FLOAT, "Men's singles" TEXT, "Women's singles" TEXT, "Men's doubles" TEXT, "Women's doubles" TEXT, "Mixed doubles" TEXT)

Who all played mixed doubles in 2010?
SELECT "Mixed doubles" FROM table_15618 WHERE "Year" = '2010'
SELECT "Mixed doubles" FROM "table_15618" WHERE "Year" = '2010'