For the GS13: you must have one year of specialized experience equivalent to the GS-12 grade level in the federal service (obtained in either private or public sector) which must include:
Merit promotion applicants must meet time-in-grade requirement as defined in 5 CFR 300, Subpart F. One year at the GS-12 level is required to meet the time-in-grade requirements for the GS 13 level. You must meet all qualification and eligibility requirements within 30 days of the closing date of this announcement. Experience refers to paid and unpaid experience, including volunteer work done through National Service programs (e.g., Peace Corps, AmeriCorps) and other organizations (e.g., professional; philanthropic; religious; spiritual; community, student, social). Volunteer work helps build critical competencies, knowledge, and skills and can provide valuable training and experience that translates directly to paid employment. You will receive credit for all qualifying experience, including volunteer experience.