Question: Which Number of electorates (2009) has a District of jhajjar, and a Reserved for (SC/ST/None) of sc, and a Constituency number smaller than 66?
SQL: SELECT COUNT(number_of_electorates__2009_) FROM table_name_56 WHERE district = "jhajjar" AND reserved_for___sc___st__none_ = "sc" AND constituency_number < 66