CREATE TABLE table_21794 ("Poll Source" TEXT, "Dates administered" TEXT, "Democrat: Jay Nixon" TEXT, "Republican: Kenny Hulshof" TEXT, "Lead Margin" TEXT)

What poll source claimed that Republican: Kenny Hulshof had 43%?
SELECT "Poll Source" FROM table_21794 WHERE "Republican: Kenny Hulshof" = '43%'
SELECT "Poll Source" FROM "table_21794" WHERE "Republican: Kenny Hulshof" = '43%'