who is the common prime minster of robert gascoyne-cecilr and peter carington ?
SELECT DISTINCT var_uri where brack_open dbr_Robert_Gascoyne-Cecil,_5th_Marquess_of_Salisbury dbo_primeMinister var_uri sep_dot dbr_Peter_Carington,_6th_Baron_Carrington dbp_primeminister var_uri brack_close