name the office holder whose predecessor is george douglas-hamilton and successor is michael hicks beach ?
SELECT DISTINCT var_uri where brack_open var_uri dbp_predecessor dbr_George_Douglas-Hamilton,_10th_Earl_of_Selkirk sep_dot var_uri dbp_successor dbr_Michael_Hicks_Beach,_2nd_Earl_St_Aldwyn sep_dot var_uri a dbo_OfficeHolder brack_close