CREATE TABLE table_1740431_3 (gregorian_months VARCHAR, season_in_tamil VARCHAR)

What is every Gregorian month when the season in Tamil is ?
SELECT gregorian_months FROM table_1740431_3 WHERE season_in_tamil = "இளவேனில்"
SELECT "gregorian_months" FROM "table_1740431_3" WHERE "season_in_tamil" = "இளவேனில்"