I have been receiving distributions for 10 years. Should I put $0 for contributions previously or the same total $ of the distributions received as they were all taxed?
It depends.
If you inherited this IRA from a spouse, you had several options including treating the IRA as your own, rolling it over, or treating yourself as the beneficiary.
If your inherited the IRA from someone else, then it would depend upon whether the IRA had basis when you inherited it. If it did, then the portion of distribution that had a basis amount would not be taxable. But any amount distributed above the basis amount would be taxable. You may need to reach out to the plan administrator if you have any questions on the basis amounts of the Inherited IRA.
Please see IRS publication 590B for and specifically the section titled What if you Inherit an IRA for more details as it applies to your specific situation.