Heading Into Iowa, Biden and Sanders Top Latest National Poll

(Bloomberg) -- Former Vice President Joe Biden is holding his lead in national polling just days ahead of the Iowa caucuses, but Vermont Senator Bernie Sanders is keeping the gap narrow.Biden takes the top spot in the latest Quinnipiac University national poll with 26% support among Democrats and Democratic-leaning voters, up slightly from 25% in a Jan. 13 survey. Sanders rose to 21% in the latest tally, up from 19% two weeks ago and his highest tally so far in the