Who is the winning team in a match held on April 26, 2009 with a winning margin of 6 points?
winning margin of 6 points refers to Win_Margin = 6; held on April 26, 2009 refers to Match_Date = '2009-04-26'
SELECT T1.Team_Name FROM Team AS T1 INNER JOIN Match AS T2 ON T1.team_id = T2.match_winner WHERE T2.Win_Margin = 6 AND T2.Match_Date = '2009-04-26'