In your name.
You hold the copyright to everything you create (with the exception of work for hire, as April points out) unless you expressly sell or transfer the copyright to another party or place it in the public domain (or if you are dead and enough time has passed).
Say someone reads your content and wants to republish it. Who do they negotiate with? The answer is you. You must honor the terms of your recent contract but you, and only you, get to set the terms of an additional one.
The company you signed the contract with in your question did not purchase a copyright transfer. They purchased the rights to publish your work along with a promise from you that you will not allow anyone else to publish it within a set period of time.
It is possible that your contract states a total transfer of copyright for X amount of time, after which all rights revert to you. But that will be explicit in your contract and is not the default. The contract may also mention how to attribute. Read it carefully.