user: Question: What is the largest base pair with a Strain of Unspecified?
Columns: ['Species', 'Strain', 'Type', 'Base Pairs', 'Genes']
Types: ['text', 'text', 'text', 'real', 'real']
Sample row: ['Borrelia burgdorferi', 'B31', 'Spirochaetes', 910724.0, 850.0]
SQL:

assistant: SELECT MAX("Base Pairs") FROM "Table" WHERE "Strain" = 'Unspecified';