CREATE TABLE table_1524 ("Poll Source" CLOB, "Dates administered" CLOB, "Democrat: Jim Martin" CLOB, "Republican: Saxby Chambliss" CLOB, "Lead Margin" FLOAT)

How many times did Saxby Chambliss have a lead margin of 21?
SELECT COUNT("Republican: Saxby Chambliss") FROM table_1524 WHERE "Lead Margin" = '21'
SELECT COUNT("Republican: Saxby Chambliss") FROM "table_1524" WHERE "Lead Margin" = '21'