Sure. If I do unsqueeze (0 ), I am having the following output:
before unsqueezing
tensor([13, 14,  9,  4])
torch.Size([4])
after unsqueezing
tensor([[13, 14,  9,  4]])
torch.Size([1, 4])

after scattering
tensor(0.)


and a following error
raise ValueError("Target size ({}) must be the same as input size ({})".format(target.size(), input.size()))
ValueError: Target size (torch.Size([15])) must be the same as input size (torch.Size([4, 15]))

Actually that is why I changed my dimension from 0 to 1