How does having a second and foreclosing work? Or... what happens if I win the bid at foreclosure auction on a second?

[Kris Fox]

I was wondering what happens in the following two scenarios.

Local foreclosure/sheriff's sale and there's a $10,000 HOA lien that is foreclosing. Let's say that the property is worth $150k and the principal on the first is $50k. What is the correct play if I'm bidding?

Same scenario as above except that the principal on the first is $125k.

I have a feeling that the answer to the next question can be inferred from the answer to the above question, but what happens if I own the second (say I bought a mechanics lien/judgement from someone) and the first is $50k and the lien I bought is worth $10k and the property is worth $150k.  

Thanks a lot guys.