Table schema:
CREATE TABLE table_name_13 (lok_sabha VARCHAR, party_affiliation VARCHAR, duration VARCHAR)

Question: What is the Lok Sabha for Dravida Munnetra Kazhagam, in 1999-04?
SQL: SELECT lok_sabha FROM table_name_13 WHERE party_affiliation = "dravida munnetra kazhagam" AND duration = "1999-04"