With such vague details to go on, your best bet is going to be placed by posting some pictures on here for members to view.
A picture of the machine from the side and one from the front might possibly get an ID from somebody as to the brand of machine.
A picture showing the broken part would help to confirm what that part is called.
Based on your description that it is "a steel rod which connects to the steering wheel" I infer that it is the "steering column shaft" or simply "steering shaft".
And then there is the possibility that the tractor is a "re-marqued" machine (built by a major OEM but sold under contract with a different "marque" for a niche market).
There is also a good possibility that there might not be any examples of the tractor to be found outside of Ireland, or the UK.
A few photos would be good for a starting point.

It could also be what AYP calls a draglink. But like mownie points out, pictures may help. Btw--do you have both ends of the broken part?

Why don't you have it welded back together.