user: Question: How many French heads of state have a head of mission of Xavier Daufresne de la Chevalerie?
Columns: ['Head of mission', 'Tenure begins', 'Tenure ends', 'French Head of State', 'Japanese emperor']
Types: ['text', 'real', 'real', 'text', 'text']
Sample row: ['Jean Daridan', 1959.0, 1961.0, 'Charles de Gaulle', 'Hirohito']
SQL:

assistant: SELECT COUNT("French Head of State") FROM "Table" WHERE "Head of mission" = 'Xavier Daufresne de la Chevalerie';