Please state your opinion on witch part of Korea would win and how.
It wouldn’t be a civil war.
Let’s think positively and hope for peace.
Neither? I can't think of any scenario that would yield a clear cut winner. The north is one of the most heavily defended pieces of real estate on the planet, they have been fortifying it for 70 plus years and they have nuclear weapons to boot. There's no realistic way it could be conquered without terrible casualties. And the North's army isn't capable of invading the south, their troops would be massacred by the South's air force if they left their fortified positions. The best thing would be to reintegrate the North back into the world community, and nature would take its course. South Korea was a military dictatorship too, that's what happened to it. The US needs enemies to justify its empire though, so doubt it will happen any time soon.
Depends on what you mean by winning? After the death of millions of people and the destruction of earth, and if China doesn't step in, then the US/ROK