CREATE TABLE table_name_15 (opponents VARCHAR2, partner VARCHAR2, surface VARCHAR2)

Which Opponents have a Partner of irina-camelia begu, and a Surface of hard?
SELECT opponents FROM table_name_15 WHERE partner = "irina-camelia begu" AND surface = "hard"
SELECT "opponents" FROM "table_name_15" WHERE "hard" = "surface" AND "irina-camelia begu" = "partner"