Two years ago, the Republican Party picked up six seats in the Oregon House of Representatives, erasing a Democratic advantage and giving each party 30 legislators in the 60-member chamber. This time around, the GOP hopes to end the tie and take back control of the House for the first time in a half dozen years. Republicans held an advantage in the House from 1991 through 2006. It may be a tough challenge, however. In each of the six districts in which Republicans picked up House seats, Democrats hold a registration edge. To win, Republicans will have to appeal to …