who is the prime minister of alexander duff who is also the minister of henry petty-fitzmaurice ?
SELECT DISTINCT var_uri where brack_open dbr_Alexander_Duff,_1st_Duke_of_Fife dbp_primeminister var_uri sep_dot dbr_Henry_Petty-Fitzmaurice,_5th_Marquess_of_Lansdowne dbo_primeMinister var_uri brack_close