It depends. The traditional IRA contribution will only decrease your AGI if your MAGI was under certain limits. To check the limits (various based on marital status and age), see Traditional IRA Tax Benefits.
If you meet the income limits, revisit the IRA contribution work area and be sure you checked the box that your contribution was for a traditional IRA, you entered the contributions in the proper year, and continue through all the interview questions. At the end of the interview, you will see Your IRA Deduction Summary, with the amount you are eligible to deduct.