Admittedly, my knowledge of Roman law is a bit lacking as I do not practice in a civil law system. The right to an attorney is a relatively modern invention, and the idea that the state should pay for the attorney for the accused is even more modern, so it's very unlikely that it would have crossed a Roman's mind to assign an attorney to plead Jesus' case. There are obviously other aspects that should be examined, like whether Roman law recognized attorneys acting on behalf of parties in the same way common law systems do and whether the biblical evidence we have for Jesus and Pilates' meeting constitutes some form of examination under Roman law.

The Sixth Amendment to the United States Constitution preserves the right of the accused to the "Assistance of Counsel" in criminal cases. (U.S. Const., Amend. VI.) Our idea of a "right to an attorney" is no doubt popularized by the 1966 case of Miranda v Arizona. (384 US 436 [1966].) In that case, the Supreme Court, in order to safeguard the Constitutional rights of criminal suspects, held that "[p]rior to any questioning, the person must be warned that he has a right to remain silent, that any statement he does make may be used as evidence against him, and that he has a right to the presence of an attorney, either retained or appointed." (Id., at 444.) That did not end the question of exactly what the "right to an attorney" meant, but America was well on its way to the right to a court-appointed attorney we are familiar with today.[1]

So it wasn't until the 1960s that we see a state-funded right to an attorney for the accused in criminal cases, making it pretty unlikely that there would be such a right in the 30s AD.

[1] Among the issues was whether the right to "the Assistance of Counsel", as required by the Sixth Amendment, meant only that a defendant had the right to have counsel present or whether the state was required to provide the accused with counsel if the accused could not afford it, a question that was settled prior to Miranda in Gideon v Wainwright in favor of the latter argument. (372 US 335 [1963].)