oil level in crankcase

[terry274]

I checked the engine oil level before I used my Super Dexta yesterday. It was about three quarters of the way to the max line. I did not top it off because I planned on changing the oil soon.
Checked the oil today and it is slightly above the max line. The oil looks normal, not milky. I did not shut the fuel tap off when I parked the tractor yesterday. Did diesel manage to leak into the crankcase, and if so what do I need to do about it? I did shut the fuel tap off today. I have not started the tractor, as I don't know what might get damaged if anything.
Suggestions?
Terry

Edit:
I removed the cold start heater plug and fuel poured out. I will change the oil and stop the fuel leak, does anything need to be done for the motor?
Thanks