In order for others to help you, you will first need to help them. John and Elizabeth are two of the most common Stewart names. Can you provide any additional details?
You said "on a census form".... which census?
Where were John and Elizabeth living?
Do you have any idea what Elizabeth's maiden surname was?
Do you know of any children? siblings? parents? neighbors?
What record sources have you already explored? If you could share that information, it will prevent others from pointing you in the direction of records you may have already checked and also prevent them wasting time doing lookups in order to help you.
Good luck to you in your genealogical endeavors.
Lauren M. Boyd, FSA Scot
Stewart Board Admin
Rootsweb Volunteer since 1996 ** Celebrating 10 yrs**