Democrat J. Bennett Johnston Jr. staved off a stronger-than-expected challenge by a virtual unknown to win election to a second term as Louisiana's junior senator.

Johnston captured 480,769 votes (59 percent) in Saturday's "open primary" election, and state Rep. Louis (Woody) Jenkins of Baton Rouge received 330,957 (41 percent) with all but 40 precincts reported.

The tally means Johnston is reelected because Louisiana's open primary law allows Democrats and Republicans to run against each other. The candidates polling more than 50 percent wins outright. In races where no one won a majority, the top two votegetters will square off Nov. 7.

In the House races Saturday, Republicans put themselves in position to take half of the state's eight seats, according to unofficial returns. Former state representative James Wilson, a Republican from Vivian, reached a runoff with Democratic state Rep. Claude Leach of Leesville in the 4th Congressional District, where Rep. Joe D. Waggoner, a Democrat, is retiring.

In other House races, first-term Rep. Jerry Huckaby. a Democrat, apparently defeated three others. He received 62.614 votes (52.4 percent), while his nearest rival, state Sen. James Brown of Ferriday, had 36,109. Huckaby had unseated veteran congressman Otto Passman in the 5th District two years ago.

Other Democrats seeking reelection won handily. Rep. Gillis Long had 79 percent in the 8th district, John Breaux 60 percent in the 7th district and Lindy Boggs 79 percent in the 2nd district.

Three Republican incumbents, in a state that has only a 5 percent Republican registration, easily won another term in Congress. Rep. Robert Livingston defeated his lone opponent with 86 percent of the vote in the 1st district, while Rep. Henson Moore captured 91 percent of the vote in the 6th district. Rep. David Treen was unopposed in the 3rd district.

In the Waggonner race, Leach, a conservative who is chairman of the House Ways and Means committee in the legislature, received heavy support from business interests who stuck with the Democratic Party.

Wilson, also a conservative, is a former Democrat who turned Republican and headed the state's right-to-work committee.

Leach led Wilson 33,956 to 33,418.

Wilson edged out Charles Roemer III, a more liberal candidate who had been expected to do better among black voters. Leach, who was late starting in the campaign because the legislative session didn't end until July, reportedly made heavy inroads among blacks.