CREATE TABLE "list_of_oldest_sitting_m_ps_since_1945" (
  "born" text,
  "became_oldest_mp" text,
  "left_house" text,
  "age_on_leaving" text,
  "died" text,
  "political_party" text
);

Question: How old was the conservative party member that left the house in 2001?
SQL: SELECT "age_on_leaving" FROM "list_of_oldest_sitting_m_ps_since_1945" WHERE "political_party"='conservative' AND "left_house"='2001';