CREATE TABLE table_19477 ("Date Released" CLOB, "Polling institute" CLOB, "Socialist" CLOB, "Social Democratic" CLOB, "Peoples Party" CLOB, "Green-Communist" CLOB, "Left Bloc" CLOB, "Lead" CLOB)

What are all percentages of Left Block when there is a 28.7% Social Democratic?
SELECT "Left Bloc" FROM table_19477 WHERE "Social Democratic" = '28.7%'
SELECT "Left Bloc" FROM "table_19477" WHERE "Social Democratic" = '28.7%'