I need to filter the column1 if it is having date in the cell,

I need to filter the column1 if it is having date in the cell, 

Column1created_date
No Activity in (31 March 2014) 2014-02-27 15:19:44.000
Just Started(28 March 2014)2014-02-27 15:19:44.000
No Activity in ()2014-02-27 15:19:49.660
Just Started()2014-02-27 15:19:49.660