Both are fine. Held is more natural in that construction, but when it’s a property which is likely to continue to the present, hold is perfectly good, and draws attention to the fact that it is still the case.

What is past participle?

In English grammar, the past participle refers to an action that was started and completed entirely in the past. It is the third principal part of a verb, created by adding -ed, -d, or -t to the base form of a regular verb.

What is the correct form of Hold?

V1 Base Form (Infinitive):To HoldV2 Past Simple:HeldV3 Past Participle:HeldV4 3rd Person Singular:HoldsV5 Present Participle/Gerund:Holding