A criminal record should not automatically rule someone out of a role that requires a DBS disclosure, though ultimately it is the decision of the employer in line with their safeguarding policies as to whether an applicant is suitable to work in the position for which they have applied.
If however your conviction included being put on the children’s or vulnerable adults’ barred lists or imposed a ban upon working in certain professions then it may be a criminal offence to pursue an application for employment in those areas.