Veritical videos getting squashed in when importing

Hi all. I hope you can help me.

I've recorded some videos on my Sony ZV-1 in portrait. Whenever I import the videos to premiere pro they end up getting squashed and cropped, so they're not their original proportions. Why does this happen and how can I fix it? 

Any help will be appreciated because it's driving me insane.

For reference, the dimensions of the videos are 607 × 1080.