CREATE TABLE table_21191 ("Months in Malayalam Era" CLOB, "In Malayalam" CLOB, "Gregorian Calendar" CLOB, "Tamil calendar" CLOB, "Saka era" CLOB, "Sign of Zodiac" CLOB)

Name the sign of zodiac for chithirai
SELECT "Sign of Zodiac" FROM table_21191 WHERE "Tamil calendar" = 'Chithirai'
SELECT "Sign of Zodiac" FROM "table_21191" WHERE "Tamil calendar" = 'Chithirai'