What are the populations of the counties they come from, please?
select T1.Population from county AS T1 JOIN election AS T2 where T1.County_Id = District and T2.Committee = 'Appropriations'
populations of the counties refers to T1.Population; counties they come from refers to joining tables county (T1) and election (T2) where T1.County_Id matches T2.District; condition 'they come from' refers to specific committee involvement, i.e., T2.Committee = 'Appropriations'.