That be the oil pressure sending unit.
I'd clean/degrease the whole area 1st, then see if you can find where it's leaking from.
There could be multiple places on the front of the engine where the oil could be leaking from:
oil pump shaft seal/weep hole
cam chain cover
oil pump joint where it joins the block
oil pressure sender
A filter cover o-ring leak wouldn't be putting oil on the front of the engine.