What is the MAGI limit traditional IRA deduct-ability for married filing jointly when only one spouse had a retirement plan for part of the year?

Facts: Only Spouse had income from work. My income was from pension and investments including RMD from a traditional IRA.  Turbo Tax suggested after doing it's review that taxes could be reduced if spouse contributed $6,500 to a traditional IRA..  Spouse did so and now Turbo Tax says our joint MAGI is too high to deduct the contribution.  In the help it indicates the MAGI limit is higher when only one spouse had a retirement plan at work., but it does not say what the increased limit is.  What is the limit in this fact situation?  Having already contributed $6,500 to a traditional IRA - if the amount is nondeductible would it be better to convert that $6500 to a Roth IRA?