A debt collector called today about a debt included in a bankruptcy 10 years ago. What do I need to do?

The collector called when I wasn't home. He answered my husbands questions about what he was calling about. They want me to call back and give the discharge # and lawyer's name. Can I be legally responsible for this debt that was discharged 10 years ago in the bankruptcy? Obviously this debt was sold to a third party collection agency. How do I need to respond to protect myself?