CREATE TABLE table_1959 ("Date Released" CLOB, "Polling institute" CLOB, "Social Democratic" CLOB, "Socialist" CLOB, "Green-Communist" CLOB, "Peoples Party" CLOB, "Left Bloc" CLOB, "Lead" CLOB)

What date did the Green-Communists receive 5.7%?
SELECT "Date Released" FROM table_1959 WHERE "Green-Communist" = '5.7%'
SELECT "Date Released" FROM "table_1959" WHERE "Green-Communist" = '5.7%'