Table: election_polls
Columns: poll_source
dates_administered
democrat_jim_martin
republican_saxby_chambliss
lead_margin

Question: What is the date administered where Saxby Chambliss is 54% and Jim Martin is 36%?
SQL: SELECT "dates_administered" FROM election_polls WHERE "republican_saxby_chambliss" = '54%' AND "democrat_jim_martin" = '36%'

Question: How many times did Saxby Chambliss have a lead margin of 21?
SQL: SELECT COUNT("republican_saxby_chambliss") FROM election_polls WHERE "lead_margin" = 21