list the leaders of all the cities through which the 2007–08 a1 grand prix of nations river flows ?
SELECT DISTINCT var_uri where brack_open dbr_2007–08_A1_Grand_Prix_of_Nations,_Shanghai,_China dbp_city var_x sep_dot var_x dbo_leaderName var_uri sep_dot var_x a dbo_City brack_close