Table schema:
CREATE TABLE table_name_51 (semi_final_second_television_commentator VARCHAR, year_s_ VARCHAR, final_television_commentator VARCHAR, spokesperson VARCHAR)

Question: Who is the semi-final second television commentator with graham norton as the final television commentator and scott mills as the spokesperson before 2013?
SQL: SELECT semi_final_second_television_commentator FROM table_name_51 WHERE final_television_commentator = "graham norton" AND spokesperson = "scott mills" AND year_s_ < 2013