CREATE TABLE table_name_75 (national_final_main_host VARCHAR(255), venue VARCHAR(255), selection_show VARCHAR(255))
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 table_name_75 WHERE venue = "bbc television centre" AND selection_show = "eurovision: your country needs you"