khalifa bin salman al khalifa and salman bin hamad bin isa al khalifa are leaders of which place ?
SELECT DISTINCT var_uri where brack_open var_uri dbo_leader dbr_Khalifa_bin_Salman_Al_Khalifa sep_dot var_uri dbo_leader dbr_Salman_bin_Hamad_bin_Isa_Al_Khalifa sep_dot var_uri a dbo_Place brack_close