get_the_category pulling wrong cat

I have a series of posts that are categorized under category ‘2005’ and sub-category ‘1:12’.

I’m pulling the name of the parent category (2005) into the sidebar of each post using

<? $category = get_the_category(); echo $category[0]->cat_name; ?>

The problem is that it’s showing the sub-category (1:12) instead of the category (2005).

I’m also pulling the sub-category name in another part using
<? $category = get_the_category(); echo $category[1]->cat_name; ?>

And that’s adding the parent instead of the sub.

The problems seems to be that the sub-category is labeled using a numbers instead of letters. For instance if I change the sub cat name to ‘one : twelve’ it works properly.

Anyone know how to fix this?
Thanks much for any feedback!