There's one customer spent 214582.17 in the June of 2013, which currency did he/she use?
June of 2013 means Date contains '201306' in the yearmonth.date of the database
SELECT T2.Currency FROM yearmonth AS T1 INNER JOIN customers AS T2 ON T1.CustomerID = T2.CustomerID WHERE T1.Date = '201306' AND T1.Consumption = 214582.17