user: Question: What is the population of the Parish, plumbland, that had a former local authority of cockermouth rural district?
Columns: ['Name', 'Status', 'Population', 'District', 'Former local authority']
Types: ['text', 'text', 'real', 'text', 'text']
Sample row: ['Above Derwent', 'Civil parish', 1207.0, 'Allerdale', 'Cockermouth Rural District']
SQL:

assistant: SELECT "Population" FROM "Table" WHERE "Former local authority" = 'cockermouth rural district' AND "Name" = 'plumbland';