It depends on where you are getting your long term disability payments from. If you are receiving this income from your employer, they would be reported to you on a W-2 and would be reported as wages in TurboTax.
Not all disability payments are taxable income. If the premiums for the policy that paid your benefits were paid by you, with after tax funds, then the benefits are not taxable. If your employer paid the premiums, or you paid with pre-tax dollars, then the benefits are taxable. If you believe the other payments were taxable, you should contact the employer or insurance company to get the appropriate tax reporting form showing FICA tax withheld.