who is the prime minister of robert gascoyne-cecil who is also the minister of john spencer-churchill ?
SELECT DISTINCT var_uri where brack_open dbr_Robert_Gascoyne-Cecil,_3rd_Marquess_of_Salisbury dbp_primeminister var_uri sep_dot dbr_John_Spencer-Churchill,_7th_Duke_of_Marlborough dbo_primeMinister var_uri brack_close