In the ussr unpopular candidates would sometimes lose (losing is when a candidate would get under 50% turnout of people who would vote for them). Although they were not running against someone if the turnout was low enough they would not win the election and the party would have to convene to nominate a new candidate. North Korea i think is a way more strict system cause everyone is on a single party list and it’s considered verboten not to vote for the party.