CREATE TABLE "table1_29474481_4" (
  "head_of_mission" text,
  "tenure_begins" real,
  "tenure_ends" real,
  "french_head_of_state" text,
  "japanese_emperor" text
);

Question: 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 "table1_29474481_4" WHERE "head_of_mission"='Xavier Daufresne de la Chevalerie';