SCHEMA:
CREATE TABLE table_name_85 (national_final_co_host VARCHAR, year_s_ VARCHAR, national_final_main_host VARCHAR, selection_show VARCHAR)
USER:
What is the name of the national final co host when David Jacobs was the National final main host, and the selection show was a song for europe in 1966?

QUERY:
SELECT national_final_co_host FROM table_name_85 WHERE national_final_main_host = "david jacobs" AND selection_show = "a song for europe" AND year_s_ = "1966"