Well oasdi is FICA for SS & Medicare tax
fit is federal income tax withholding. You get credit on your tax return for it.
Sounds like you will get a W2 at the end of the year for it and you enter it in as wages. Check with your employer or disability plan.
Disability pay is taxable if the disability policy was paid for by your employer as an employee benefit. You are having taxes withheld as if it was a paycheck for working, and you should expect to get a W-2 at the end of the year and file a tax return reporting this as taxable income as if it was from working.
If you had a private disability policy that you paid for out-of-pocket (after tax, not as a pre-tax payroll deduction) then it should not be taxable and you should contact the insurance company.