Conversation so far:
Have you ever heard of Alexander Haig?
Alexander Haig was born in Bala Cynwyd, Pennsylvania, the middle of three children of Alexander Meigs Haig Sr., a Republican lawyer of Scottish descent, and his wife, Regina Anne
How old was Alexander Haig when his father died?
Alexander Haig was 9 years old

Question: What president did Haig serve for?
Self-contained rewrite: What president did Alexander Haig serve for?