As Volvogirl said, Roth contributions are made with post-tax dollars, so they are not deductible. The benefit is that the contributions and earnings on them are tax-free when you take a withdrawal.
You may be eligible to take the Saver's Credit for those Roth contributions, if you qualify. There are income limitations which disqualify many taxpayers from this credit, but definitely check to see if you qualify. More information and the income limits can be found here: Saver's Credit