user: Question: What is the lowest Lead Margin when Republican: Mitch Daniels was polling at 48%?
Columns: ['Poll Source', 'Dates administered', 'Democrat: Jill Long Thompson', 'Republican: Mitch Daniels', 'Lead Margin']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['Public Policy Polling', 'November 2, 2008', '37%', '60%', 23.0]
SQL:

assistant: SELECT MIN("Lead Margin") FROM "Table" WHERE "Republican: Mitch Daniels" = '48%';