CREATE TABLE table_203_755 (id DECIMAL, "singing position" DECIMAL, "song title" TEXT, "informal translation" TEXT, "act" TEXT, "percentage of votes" TEXT, "final position" TEXT)

which song did not have more than 15 % of the votes and was not unknown ?
SELECT "song title" FROM table_203_755 WHERE "percentage of votes" <= 15
SELECT "song title" FROM "table_203_755" WHERE "percentage of votes" <= 15