WASHINGTON (CNN) -- The percentage of likely voters who plan to vote for Democrats in Tuesday's congressional elections increased in the past week, and those voters supporting Democrats also seem less likely to change their minds before casting ballots, according to a CNN poll conducted over the weekend. Democrats hold a 58 percent to 38 percent advantage over Republicans among likely voters in the survey released Monday morning, compared to the 53 percent to 42 percent advantage reflected in the poll a week ago. Pollsters asked people who wires.send-nat-b wires.send-nat-b identified themselves as being likely to vote which party's candidate...