Had a quick look.  It turns out that Intuit didn't program any toggle for AL, unlike some other states.

If it is of those that are eligible for exemption, you will just override the state taxable amount as @George4Tacks suggested.

This can be done either:

• Under Income > Pensions, IRAs (1099-R), on the line State taxable amount, if different; or
• Under State & Local > Income > AL Income, on the line Alabama taxable pensions (Form 40, line 5b) [Override]