Texas statutes state, "A person whose criminal
history record information has been sealed under this section is not required in any application for employment, information, or licensing to state that the person has been the subject of any criminal proceeding related to the information that is the subject of an order issued under this section." TGC 411.081(g-2).
BUT, three problems with that: (1) the federal government is not bound by Texas law, (2) other provisions of the act allow disclosure of sealed records to other criminal justice
agencies and some non-criminal justice agencies, and (3) failure to disclose it may be a federal crime.
If you have to fill out a SF-86 (link below), it specifically states that, "For this item, report information regardless of whether the record in your case has been "sealed" or otherwise stricken from the court
record." It also provides that, "The U.S. Criminal Code (title 18, section 1001) provides that knowingly falsifying or concealing a material fact is a felony which may result in fines of up to $10,000, and/or 5 years imprisonment, or both."
Federal law always trumps state law if there is a conflict between the two because of the Supremacy Clause of the U.S. Constitution. Thus, the botXXXXX XXXXXne is that you should disclose it under these circumstances.
A felony conviction would likely disqualify you, but I do not think it is a foregone conclusion that a deferred adjudication on a misdemeanor will result in denial of your security clearance.
Good luck to you.