Bernie Sanders has drawn huge crowds on the campaign trail and seems to be an actual challenge to Hillary Clinton in some early primary states. But the Vermont senator is far behind in another key race -- the one to secure so-called superdelegates at the party's convention.

So far, Clinton has pocketed 359 of the roughly 700 Democratic elected officials and heavyweights who will have a vote when the party gathers in Philadelphia from July 25 to 28 of next year. Sanders, on the other hand, just announced his 11th superdelegate backer, the Washington Post reported.

Erin Bilbray, a member of the Democratic National Committee from Nevada, almost ended up being the former secretary of state's 360th vote but ultimately decided to support Sanders due to his his stance on money in politics and his focus on grassroots campaigning, the newspaper noted.

"It really was a deep struggle," Bilbray admitted.

While both Democrats and Republicans will hold national conventions next summer to determine their respective White House nominee, only the Democratic event will feature superdelegates, the Observer noted. They account for roughly 15 percent of the total 4,763 delegates, and roughly 30 percent of the 2,382 delegates needed to clinch the Democratic nomination.

But having an edge over superdelegates is no guarantee, NPR pointed out. The radio network recalled that in 2008, Clinton, then a senator from New York, had an advantage among these party elders in her race against then-Illinois Sen. Barack Obama. Nevertheless, Obama eventually won the nomination and the general election to become president.

Besides Bilbray, the 11 superdelegates currently backing Sanders also include the senator himself, according to the Associated Press. The newswire had contacted approximately 80 percent of what is said were 712 superdelegates.

Two hundred and ten delegates remain undecided, and two said they backed the third Democratic presidential hopeful, Martin O'Malley.