Hello Hartland,
As Nanny Jan has already said:- "It could be that either whoever filled in his details thought that was where he was born, or, if his family had moved when he was very young he might have thought he was born in Stafford, but it was actually in the Dudley area".
On the 1901 census there is a John & Ada Baldwin, plus children, living in Ryder Street, Birmingham. John's occupation is Tube Trade (drawer) and it's stated that he was born in Birmingham. If you want the details just let me know.
Being born and brought up in Dudley before my marriage, Dudley has never been, as far as I am aware, been in Staffordshire, always Worcestershire and now West Midlands.
Dudley Castle was always said to be in Staffordshire; the Castle surrounded by Worcestershire and Worcestershire surrounded by Staffordshire.
Lupo