[rustbucket]

As I remember, Lincoln introduced legislation while he was in Congress to end slavery in Washington DC.

[Ditto]

Yes he did, in the late 40s when he was a one-term Congresscritter. It was, of course, never brought to a vote thanks to the fact that the Slave Power gag order was still in force. Being that Washington DC was an entirely Federal entity until recent times, a simple resolution of congress, signed by the president, could have ended slavery within the District at any moment.

On becoming President, Lincoln did propose and sign legislation that did immediately end slavery in the Federal District.

He also used all of his powers (which weren't much beyond persuasion) to end it in the loyal "Border States"

Here's a link if you are really interested in understanding that the man really did want to end slavery, as opposed to the neo-confederate myths of the "Tyrant and Dictator" who only wanted to punish the poor South and didn't care about slavery in the "North." He quite literally begged for their help in ending it in their states.

Appeal to the Border States