name a office holder whose predecessor is dudley ryder and has son named austen chamberlain ?
SELECT DISTINCT var_uri where brack_open var_uri dbo_predecessor dbr_Dudley_Ryder,_3rd_Earl_of_Harrowby sep_dot var_uri dbo_child dbr_Austen_Chamberlain sep_dot var_uri a dbo_OfficeHolder brack_close