CREATE TABLE table_name_64 (population INTEGER, area__km_2__ VARCHAR(255), type VARCHAR(255), name VARCHAR(255))
Saint-Blaise-Sur-Richelieu is smaller than 68.42 km^2, what is the population of this type M municipality?
    
SQL: SELECT MIN(population) FROM table_name_64 WHERE type = "m" AND name = "saint-blaise-sur-richelieu" AND area__km_2__ < 68.42