Let's say When my first bet wins, my second will not be counted because my second bet is below current bankroll?!
Also Directbet has max bet limit, what if I make 10x roi?
No it will be counted. That's because the 1% minimum bet is calculated based on your available bankroll at the time when you place the bet and not when the previous bet settles.
So if for example your available bankroll is 1030 mBTC and you place two bets of 10.3 mBTC each, or any number of bets of 10.3 mBTC each they would all be counted regardless of the bets result.
The leaderboard shows you how much you have "available" to bet. All you need to do is make sure it's 1% or more of that amount.
It's actually a good rule because it helps ensuring a fair competition and prevents abuse.
It's extremely unlikely that the minimum bet required will be larger than the max bet size allowed for the bet and even then it is usually possible to bet more than the max quoted bet size.