CREATE TABLE table_17538810_10 (lead_margin VARCHAR, dates_administered VARCHAR)

How many different lead margins were stated in the poll administered on September 11, 2008?
SELECT COUNT(lead_margin) FROM table_17538810_10 WHERE dates_administered = "September 11, 2008"
SELECT COUNT("lead_margin") FROM "table_17538810_10" WHERE "September 11, 2008" = "dates_administered"