is there any way to defend yourself against a law that's being applied in certain way to a person by previous trials by other judges, and then when you are being judged for the same action and you are found guilty? Can the previous trials be used as example to defend yourself to appeal the judgment in higher instances of court?
This article summarizes the status of precedent in Argentine law, which appears to be "special". As he says, there is a system of (very) "soft precedent", and the Argentine Supreme Court has repeatedly said that lower courts are not obliged to follow their rulings, but if you don't you run the risk of your decisions being struck down. Which seems to mean that lower courts should check what the Supreme Court has said, but you can diverge from those findings if you have a new argument, or other good reason. In the US and other common law jurisdictions, courts will also follow decisions by other courts at the same level of the hierarchy (not just superior courts), but in Argentina, there is no horizontal stare decisis.
Under the inquisitorial system, the court is part of the investigation, so you can discuss with them analogous facts. Apparently, however, that is the old system, since 3 years ago Argentina switched to an adversarial system, and I think this is the new Code of Criminal Procedure. My impression is that adversarial systems have stricter procedures. So it is possible that you would be blocked by rule from introducing any such argument.