Table schema:
CREATE TABLE table_17289604_38 (round_of_64 VARCHAR, athlete VARCHAR, event VARCHAR, round_of_16 VARCHAR)

Question: What was round of 64 of the singles event when the result of round 16 was did not advance and the athlete was Iveta Benešová?
SQL: SELECT round_of_64 FROM table_17289604_38 WHERE event = "Singles" AND round_of_16 = "Did not advance" AND athlete = "Iveta Benešová"