CREATE TABLE table_29474481_4 (french_head_of_state VARCHAR(255), head_of_mission VARCHAR(255))
How many French heads of state have a head of mission of Xavier Daufresne de la Chevalerie?
    
SQL: SELECT COUNT(french_head_of_state) FROM table_29474481_4 WHERE head_of_mission = "Xavier Daufresne de la Chevalerie"