CREATE TABLE table_21468 ("Athlete" TEXT, "Event" TEXT, "Round of 64" TEXT, "Round of 32" TEXT, "Round of 16" TEXT, "Quarterfinals" TEXT)

What was round of 64 of the singles event when the result of round 16 was did not advance and the athlete was Iveta Bene ov ?
SELECT "Round of 64" FROM table_21468 WHERE "Event" = 'Singles' AND "Round of 16" = 'Did not advance' AND "Athlete" = 'Iveta Benešová'
SELECT "Round of 64" FROM "table_21468" WHERE "Athlete" = 'Iveta Benešová' AND "Event" = 'Singles' AND "Round of 16" = 'Did not advance'