Question: Calculate the difference between the 2020 population and the 2010 population for the districts represented by Griffin Tim.
SQL: SELECT T1.population_2020 - T1.population_2010 FROM zip_data AS T1 INNER JOIN zip_congress AS T2 ON T1.zip_code = T2.zip_code INNER JOIN congress AS T3 ON T2.district = T3.cognress_rep_id WHERE T3.first_name = 'Griffin' AND T3.last_name = 'Tim'