WASHINGTON — North Dakota Sens. Kent Conrad, a Democrat, and John Hoeven, a Republican, sit on opposite sides of the aisle, but this week they’re coming together on one issue: foreign exchange. Both senators voted in favor of a new bill aimed at pressuring China to up the value of its currency. If passed, the legislation would give the Treasury Secretary Tim Geither the ability to take action against countries he deems as intentionally undervaluing their currency.