Definition of a Supervisor (and a lead employee)
This is for California State University (CSU) Employees. This is from California Government Code, Section 3580.3 I believe violation of this constitutes an unfair labor practice.
3580.3. "Supervisory employee" means any individual, regardless of the job description or title, having authority, in the interest of the employer to hire, transfer, suspend, lay off, recall, promote, discharge, assign, reward, or discipline other employees, or responsibility to direct them, or to adjust their grievances, or effectively to recommend such action, if, in connection with the foregoing, the exercise of such authority is not of a merely routine or clerical nature, but requires the use of independent judgment. With respect to faculty or academic employees, any department chair, head of a similar academic unit or program, or other employee who performs the foregoing duties primarily in the interest of and on behalf of the members of the academic department, unit or program, shall not be deemed a supervisory employee solely because of such duties; provided, that with respect to the University of California and Hastings College of the Law, there shall be a rebuttable presumption that such an individual appointed by the employer to an indefinite term shall be deemed to be a supervisor. Employees whose duties are substantially similar to those of their subordinates shall not be considered to be supervisory employees.
This section defines and expands upon the duties of both a supervisor and a lead employee. The key part of this that defines a lead is that the lead's duties shall be "of a merely routine or clerical nature." If you feel you have been assigned inappropriate duties, or are being managed by someone who has, you should contact a union steward.