What are the name and code of the location with the smallest number of documents?
SELECT T2.location_name ,  T1.location_code FROM Document_locations AS T1 JOIN Ref_locations AS T2 ON T1.location_code  =  T2.location_code GROUP BY T1.location_code ORDER BY count(*) ASC LIMIT 1
SELECT T2.location_name ,  T1.location_code FROM Document_locations AS T1 JOIN Ref_locations AS T2 ON T1.location_code  =  T2.location_code GROUP BY T1.location_code ORDER BY count(*) ASC LIMIT 1
[{'Location_Name': 'Nanjing', 'Location_Code': 'n'}]