Question: Give the religion of the legislator with RSS url of http://www.corker.senate.gov/public/index.cfm/rss/feed.
SQL: SELECT T1.religion_bio FROM current AS T1 INNER JOIN `current-terms` AS T2 ON T1.bioguide_id = T2.bioguide WHERE T2.rss_url = 'http://www.corker.senate.gov/public/index.cfm/rss/feed' GROUP BY T1.religion_bio