According to BIP-30 it's said, that new transaction with the same txid of unspent one won't replace that one, that's still unspent. But what is happening to this new tx that must be inculded to the chain? Miners are holding this new one in the mempool and this tx is waiting for the moment when the existing one with the same txid will be removed from LevelDB that is in chainstate folder? (I'm talking not of doublespending of the same transaction but when it's two different transactions and they have the same txid)