name the person whose mother name is elżbieta konstancja potulicka and has a son named zofia sapieha ?
SELECT DISTINCT var_uri where brack_open var_uri dbo_parent dbr_Elżbieta_Konstancja_Potulicka sep_dot var_uri dbo_child dbr_Zofia_Sapieha sep_dot var_uri a dbo_Person brack_close