Table: eurovision_1956
Columns: year_s
selection_show
venue
national_final_main_host
national_final_co_host
semi_final_heat_host

Question: What was the venue when David Jacobs was the host?
SQL: SELECT "venue" FROM eurovision_1956 WHERE "semi_final_heat_host" = 'david jacobs'

Question: What was the host for the semi final heat, when Terry Wogan was the National Final main host, and Gaby Roslin was the National Final co-host?
SQL: SELECT "semi_final_heat_host" FROM eurovision_1956 WHERE "national_final_main_host" = 'terry wogan' AND "national_final_co_host" = 'gaby roslin'

Question: What is the name of the national final main host when the semi final/heat host shows internal selection in 2011?
SQL: SELECT "national_final_main_host" FROM eurovision_1956 WHERE "semi_final_heat_host" = 'internal selection' AND "year_s" = '2011'

Question: 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?
SQL: SELECT "national_final_co_host" FROM eurovision_1956 WHERE "national_final_main_host" = 'david jacobs' AND "selection_show" = 'a song for europe' AND "year_s" = '1966'

Question: What is the selection show in 1969 when the Semi final/heat host shows there was no semi final/heat.
SQL: SELECT "selection_show" FROM eurovision_1956 WHERE "semi_final_heat_host" = 'no semi final/heat' AND "year_s" = '1969'

Question: What is the name of the national final main host at BBC Television Centre, and the selection show was Eurovision: Your Country Needs You?
SQL: SELECT "national_final_main_host" FROM eurovision_1956 WHERE "venue" = 'bbc television centre' AND "selection_show" = 'eurovision: your country needs you'