「ひまがあったら」vs. 「ひまだったら」

[WhiteDay]

I have a question about this sentence.

ひまがあったら、ぜひ東京へあそびに 来てください。

[= If you are free, please come to visit Tokyo.]

I was wondering why it is not ひまだったら、ぜひ東京へあそびに 来てください。instead.

Or is both correct? Then what's the slightest difference between them?

Please kindly help,
ありがとうございます

WhiteDay

[RadioKid]

They are both correct.

When translated strictly, they are

ひまがあったら : if you have any free time,
ひまだったら : if you are free,