Louisiana will not know which candidate will represent the state in the next Congress until December. Democratic Sen. Mary Landrieu and Republican Rep. Bill Cassidy will face off in a runoff next month, the news networks projected. Both candidates slugged it out thorugh the night, but neither was able to score a knockout over the other. The winning candidate had to win 50 percent plus one vote in the election. The polls suggested a runoff for weeks, with a third candidate, the Tea Party-backed Rob Maness, pulling enough votes from the right to keep the two main candidates neck-and-neck. A number of polls suggest Landrieu is likely to lose a runoff.