。
She had a radio.
Literal
[topic-は] radio [object-を] was-holding.
持つ literally 'to hold' takes ~ていた to express 'had/possessed' as a continued state in the past. Japanese typically uses 持っている rather than just 持つ for ownership/possession — the bare form 持つ tends to mean the moment of taking up rather than the state of having. This is a common pattern with stative-like verbs: 知る ('come to know') → 知っている ('know'), similarly.