Staunch looking character furthest left appears to be the favored. He prefers dialogue with N.Korea. His history regarding the USA though isn't exactly favorable as He wants to take the lead on whatever is determined regarding the North.....
The man on the left side is a conservative with furious last spurt. He has probably closed a gap considerably by now, but it is not clear if that would be enough. He certainly has had momentum on his side, but there was not enough time. S. Korean election has always had last minute dramatic episodes which could shake up the course of events. Sometime it upends the trend and creates a dramatic upset. Not sure what will happen this time around. Whoever wins, it won't be the end of story. There are many people who see the guy on the right side in the photo poses the existential danger to the country.